MCQs on Physical Examination of Urine

1. Which of the following is the normal color of freshly voided urine?

• A) Red
• B) Pale yellow
• C) Dark brown
• D) Green
Answer: B) Pale yellow
Explanation: Fresh urine is pale yellow due to urochrome pigment, formed from hemoglobin metabolism. Color may vary with hydration, diet, drugs, or pathology. Dark brown indicates bile pigments, red suggests hematuria or porphyrins, while green may be due to Pseudomonas infection or certain medications.

2. Which pigment is primarily responsible for the normal yellow color of urine?

• A) Bilirubin
• B) Urobilinogen
• C) Urochrome
• D) Hemoglobin
Answer: C) Urochrome
Explanation: Urochrome, a product of hemoglobin breakdown, imparts the normal yellow color of urine. Its concentration depends on hydration status. Increased urochrome deepens the color, while diluted urine appears almost colorless. Bilirubin and hemoglobin alter urine color pathologically, while urobilinogen contributes minimally.

3. What is the normal appearance of freshly voided urine?

• A) Cloudy
• B) Turbid
• C) Clear
• D) Milky
Answer: C) Clear
Explanation: Normal freshly voided urine is clear due to absence of suspended particles. Cloudiness may result from phosphates, urates, pus, or bacteria. Milky urine indicates chyluria or lipiduria. Turbid appearance is often linked to urinary tract infections or heavy cellular content.

4. Which urine odor is classically associated with uncontrolled diabetes mellitus?

• A) Fruity
• B) Ammoniacal
• C) Putrid
• D) Fishy
Answer: A) Fruity
Explanation: Fruity odor of urine in diabetes is due to presence of ketone bodies (acetone). Ammoniacal odor arises when urine is left standing because urea decomposes into ammonia. Fishy odor occurs in trimethylaminuria or some UTIs. Putrid odor suggests bacterial infection or pus contamination.

5. A strong ammoniacal odor in urine is due to:

• A) Bile salts
• B) Urea decomposition
• C) Ketones
• D) Proteinuria
Answer: B) Urea decomposition
Explanation: Ammoniacal odor develops when urea is converted to ammonia by bacterial urease action in standing urine. It suggests improper storage or infection. Ketones cause fruity odor, bile salts rarely change smell, and proteinuria may cause musty odor but not ammonia-like odor.

6. Cloudy urine with a white, milky appearance is most likely due to:

• A) Proteinuria
• B) Chyluria
• C) Hematuria
• D) Bilirubinuria
Answer: B) Chyluria
Explanation: Chyluria, caused by lymphatic obstruction (e.g., filariasis), results in milky-white urine due to presence of chyle. Hematuria gives red urine, bilirubinuria gives dark yellow-brown urine, while proteinuria causes slight turbidity but not milky appearance. Microscopic examination confirms fat globules in chyluria.

7. The specific gravity of normal urine ranges from:

• A) 1.000–1.005
• B) 1.005–1.030
• C) 1.030–1.050
• D) 1.050–1.070
Answer: B) 1.005–1.030
Explanation: Normal urine specific gravity ranges 1.005–1.030, reflecting solute concentration. Low values (<1.005) suggest dilute urine or diabetes insipidus, while high values (>1.030) indicate dehydration, glycosuria, or proteinuria. Persistent fixed specific gravity around 1.010 suggests renal concentrating defect, seen in chronic kidney disease.

8. Persistent low specific gravity of urine is a feature of:

• A) Diabetes insipidus
• B) Dehydration
• C) Glycosuria
• D) Hepatic failure
Answer: A) Diabetes insipidus
Explanation: Diabetes insipidus is characterized by impaired water reabsorption due to ADH deficiency or resistance, leading to excretion of dilute urine with persistently low specific gravity (<1.005). Dehydration and glycosuria increase specific gravity, while hepatic failure alters urine color, not gravity.

9. A reddish-brown urine turning black on standing suggests:

• A) Myoglobinuria
• B) Hematuria
• C) Alkaptonuria
• D) Porphyria
Answer: C) Alkaptonuria
Explanation: In alkaptonuria, homogentisic acid excreted in urine oxidizes to form dark pigment on standing, turning urine black. Hematuria gives fresh red urine, porphyria produces port-wine color, and myoglobinuria gives brownish-red urine without darkening on prolonged exposure.

10. Turbidity in urine due to phosphates disappears on:

• A) Adding acid
• B) Adding alkali
• C) Heating
• D) Cooling
Answer: A) Adding acid
Explanation: Cloudy urine due to phosphates clears upon acidification because phosphates dissolve in acidic medium. Urates dissolve on heating, while alkali increases phosphate precipitation. Cooling promotes urate precipitation, not phosphates. This simple bedside test helps differentiate cause of turbidity.

11. Which of the following conditions causes urine to appear dark brown or cola-colored?

• A) Hematuria
• B) Myoglobinuria
• C) Bile pigmenturia
• D) All of the above
Answer: D) All of the above
Explanation: Dark brown urine may be due to hematuria (intact RBCs), myoglobinuria (muscle injury), or bile pigments (liver disease). Differentiation requires microscopy and chemical testing. Myoglobin gives positive heme dipstick without RBCs, while bilirubinuria associates with jaundice and positive bile pigment test.

12. Which test is used to measure urine specific gravity at bedside?

• A) Dipstick test
• B) Refractometer
• C) Microscopy
• D) Benedict’s test
Answer: B) Refractometer
Explanation: A refractometer measures urine specific gravity quickly and accurately by determining refractive index of solutes. Dipstick gives approximate values, microscopy identifies cells/casts, and Benedict’s test detects reducing sugars, not specific gravity. Refractometer is preferred in clinical laboratories.

13. Urine with a sweet, maple syrup-like odor is seen in:

• A) Diabetes mellitus
• B) Maple Syrup Urine Disease
• C) Cystinuria
• D) Tyrosinemia
Answer: B) Maple Syrup Urine Disease
Explanation: Maple Syrup Urine Disease (MSUD) is an inborn error of branched-chain amino acid metabolism. Accumulated leucine, isoleucine, and valine impart a characteristic maple syrup odor to urine. Diabetes mellitus produces fruity odor, cystinuria gives sulfur smell, and tyrosinemia alters color, not odor.

14. Normal daily urine output in adults is approximately:

• A) 100–500 mL
• B) 500–1500 mL
• C) 800–2000 mL
• D) 2500–4000 mL
Answer: C) 800–2000 mL
Explanation: Normal adult urine output ranges 800–2000 mL/day depending on fluid intake and activity. Polyuria is >2500 mL/day, oliguria <400 mL/day, and anuria <100 mL/day. Monitoring output helps assess renal function, hydration, and systemic diseases.

15. A port-wine colored urine is characteristic of:

• A) Porphyria
• B) Hemoglobinuria
• C) Bile pigmenturia
• D) Alkaptonuria
Answer: A) Porphyria
Explanation: In porphyria, accumulation of porphyrins in urine gives a reddish or port-wine color that darkens on exposure to light. Hemoglobinuria produces reddish-brown urine, bilirubinuria produces dark yellow-green urine, and alkaptonuria turns black on standing due to homogentisic acid.

16. Milky urine seen in chyluria results from:

• A) Lipid droplets
• B) Uric acid crystals
• C) Hemoglobin
• D) Bile pigments
Answer: A) Lipid droplets
Explanation: Chyluria is caused by leakage of lymphatic fluid into urine, producing lipid-rich urine with milky appearance. It is commonly associated with filarial infection. Uric acid crystals produce turbidity, hemoglobin causes red-brown urine, and bile pigments cause dark brown coloration.

17. What is the significance of persistent fixed specific gravity at 1.010?

• A) Normal urine concentration
• B) Chronic renal failure
• C) Diabetes insipidus
• D) Dehydration
Answer: B) Chronic renal failure
Explanation: Fixed specific gravity around 1.010 (isosthenuria) indicates loss of renal concentrating ability, commonly seen in chronic kidney disease. Diabetes insipidus produces very low gravity, dehydration raises it, while normal values fluctuate with intake. Thus, isosthenuria reflects severe renal impairment.

18. Red urine that clears after centrifugation indicates:

• A) Hemoglobinuria
• B) Hematuria
• C) Myoglobinuria
• D) Bile pigmenturia
Answer: B) Hematuria
Explanation: In hematuria, red urine clears after centrifugation because intact RBCs settle, leaving clear supernatant. In hemoglobinuria and myoglobinuria, urine remains red after centrifugation since pigments stay dissolved. Bile pigmenturia causes brownish urine unrelated to sedimentation.

19. Which urine abnormality is commonly seen in obstructive jaundice?

• A) Colorless urine
• B) Dark yellow-green urine
• C) Fruity-smelling urine
• D) Milky urine
Answer: B) Dark yellow-green urine
Explanation: In obstructive jaundice, conjugated bilirubin is excreted in urine, imparting a dark yellow to greenish-brown color. This differs from hematuria (red), chyluria (milky), or diabetes (fruity odor). The urine also shows positive bile pigment and bile salt tests.

20. Which factor most influences urine color under physiological conditions?

• A) Urochrome concentration
• B) Bilirubin excretion
• C) Hemoglobin breakdown
• D) Diet alone
Answer: A) Urochrome concentration
Explanation: Urochrome, the primary pigment derived from hemoglobin catabolism, determines urine color. Higher concentration deepens yellow shade, while diluted urine appears nearly colorless. Bilirubin and hemoglobin alter color pathologically, while diet influences but does not dominate under normal physiology.

21. Which of the following best describes oliguria?

• A) <100 mL/day
• B) <400 mL/day
• C) <800 mL/day
• D) <2000 mL/day
Answer: B) <400 mL/day
Explanation: Oliguria is defined as urine output less than 400 mL/day in adults. It indicates decreased renal perfusion, prerenal causes like dehydration or shock, or intrinsic renal failure. Anuria is <100 mL/day, normal output is 800–2000 mL/day, and polyuria is >2500 mL/day.

22. Polyuria is defined as daily urine output exceeding:

• A) 1500 mL
• B) 2000 mL
• C) 2500 mL
• D) 3000 mL
Answer: C) 2500 mL
Explanation: Polyuria is urine output >2500 mL/day in adults. It is seen in diabetes mellitus (osmotic diuresis), diabetes insipidus (ADH deficiency or resistance), and excessive fluid intake. Normal output ranges 800–2000 mL/day. Values between 2000–2500 may be physiologic depending on hydration.

23. Urine volume <100 mL/day is termed:

• A) Oliguria
• B) Polyuria
• C) Anuria
• D) Nocturia
Answer: C) Anuria
Explanation: Anuria is urine output less than 100 mL/day, reflecting severe renal failure, obstruction, or shock. Oliguria is <400 mL/day, while nocturia refers to increased night-time urination. Anuria is a medical emergency requiring prompt evaluation of renal function and urinary tract patency.

24. Which condition typically causes high specific gravity urine (>1.030)?

• A) Diabetes insipidus
• B) Dehydration
• C) Chronic renal failure
• D) Water intoxication
Answer: B) Dehydration
Explanation: In dehydration, water loss concentrates solutes, increasing urine specific gravity >1.030. In contrast, diabetes insipidus produces dilute urine, chronic renal failure shows fixed isosthenuria around 1.010, and water intoxication lowers specific gravity due to excess water intake.

25. Which physical examination finding of urine suggests presence of pus cells?

• A) Fruity odor
• B) Turbid appearance
• C) Port-wine color
• D) Green fluorescence
Answer: B) Turbid appearance
Explanation: Pus cells (pyuria) cause urine turbidity. Cloudiness may also result from bacteria, phosphates, or urates. Microscopic examination confirms pus cells. Fruity odor suggests ketonuria, port-wine color indicates porphyria, and green fluorescence occurs in riboflavin excretion or bacterial infection with Pseudomonas.

26. Dark yellow urine with green foam upon shaking is most characteristic of:

• A) Hematuria
• B) Myoglobinuria
• C) Bilirubinuria
• D) Chyluria
Answer: C) Bilirubinuria
Explanation: Conjugated bilirubin in urine imparts dark yellow to brown color. On shaking, it produces stable green foam. This is diagnostic of obstructive jaundice. Hematuria produces red urine, myoglobinuria causes reddish-brown urine, and chyluria gives milky appearance due to lymph.

27. The characteristic sulfur odor of urine is associated with:

• A) Phenylketonuria
• B) Cystinuria
• C) Alkaptonuria
• D) Diabetes mellitus
Answer: B) Cystinuria
Explanation: Cystinuria, a metabolic defect in cystine reabsorption, leads to cystine stone formation and sulfur odor in urine. Phenylketonuria gives mousy odor, alkaptonuria causes black urine on standing, and diabetes mellitus produces fruity odor from ketone bodies.

28. Mousy odor of urine is seen in:

• A) Alkaptonuria
• B) Phenylketonuria
• C) Cystinuria
• D) MSUD
Answer: B) Phenylketonuria
Explanation: Phenylketonuria (PKU), an inborn error of phenylalanine metabolism, produces phenylacetic acid, giving urine a characteristic mousy or musty odor. MSUD gives maple syrup odor, cystinuria produces sulfur odor, and alkaptonuria changes color rather than odor.

29. Freshly voided urine is typically:

• A) Slightly acidic
• B) Neutral
• C) Slightly alkaline
• D) Strongly alkaline
Answer: A) Slightly acidic
Explanation: Normal freshly voided urine is slightly acidic (pH 5.5–6.5) due to metabolic acid excretion. Diet, metabolism, and infections influence pH. Vegetarian diet produces alkaline urine, while high-protein diet increases acidity. Prolonged standing makes urine alkaline due to bacterial urea breakdown.

30. A urine pH consistently above 7.5 suggests:

• A) Diabetes mellitus
• B) Urinary tract infection with urea-splitting bacteria
• C) High-protein diet
• D) Ketosis
Answer: B) Urinary tract infection with urea-splitting bacteria
Explanation: Urea-splitting bacteria (Proteus, Klebsiella) convert urea into ammonia, raising urine pH above 7.5. Diabetes mellitus and ketosis produce acidic urine, while high-protein diet lowers pH. Persistent alkalinity predisposes to phosphate and struvite stone formation.

31. Which of the following increases urine acidity?

• A) Vegetarian diet
• B) High-protein diet
• C) UTI with Proteus
• D) Renal tubular acidosis
Answer: B) High-protein diet
Explanation: High-protein diets generate sulfuric and phosphoric acids, making urine more acidic. Vegetarian diet rich in alkaline salts increases urine pH. UTI with urea-splitting bacteria raises alkalinity. Renal tubular acidosis paradoxically causes alkaline urine due to defective acid secretion.

32. Which crystal precipitates in acidic urine?

• A) Triple phosphate
• B) Ammonium biurate
• C) Uric acid
• D) Calcium phosphate
Answer: C) Uric acid
Explanation: Uric acid crystals form in acidic urine and appear as yellow to red-brown rhomboids. Triple phosphate and calcium phosphate precipitate in alkaline urine, while ammonium biurate is also alkaline-associated. Identifying crystals helps in diagnosis of metabolic disorders and stone disease.

33. Which crystals are typically found in alkaline urine?

• A) Uric acid
• B) Calcium oxalate
• C) Triple phosphate
• D) Cystine
Answer: C) Triple phosphate
Explanation: Triple phosphate (magnesium ammonium phosphate) crystals form in alkaline urine, appearing as “coffin-lid” shaped under microscopy. Uric acid forms in acidic urine, calcium oxalate can appear in any pH, and cystine crystals occur in acidic urine due to cystinuria.

34. The normal urine pH range is:

• A) 3.0–4.0
• B) 4.5–8.0
• C) 6.0–9.0
• D) 7.0–9.5
Answer: B) 4.5–8.0
Explanation: Normal urine pH ranges between 4.5 and 8.0, with average 5.5–6.5. Acidic urine (<5.0) occurs in ketoacidosis, diarrhea, or high-protein diets, while alkaline urine (>8.0) occurs in vegetarian diets or UTIs with urease-producing bacteria. Extremes outside range are pathological.

35. The foam test is primarily used to detect:

• A) Bile salts
• B) Glucose
• C) Ketones
• D) Proteins
Answer: D) Proteins
Explanation: When urine is shaken, persistent white foam indicates proteinuria due to stable protein-air interfaces. Yellow-green foam suggests bile pigments. Glucose and ketones do not produce stable foam. Foam test is a quick bedside screening for protein in urine.

36. Which condition gives urine a smoky or cola-colored appearance?

• A) Hematuria from glomerulonephritis
• B) Cystinuria
• C) Diabetes mellitus
• D) Porphyria
Answer: A) Hematuria from glomerulonephritis
Explanation: In glomerulonephritis, RBCs undergo hemolysis in acidic urine, producing smoky or cola-colored urine. Fresh bright-red urine suggests lower tract bleeding. Porphyria produces port-wine urine, cystinuria causes sulfur odor, and diabetes gives fruity-smelling urine.

37. Which of the following produces greenish urine?

• A) Biliverdin excretion
• B) Pseudomonas infection
• C) Certain drugs (e.g., methylene blue)
• D) All of the above
Answer: D) All of the above
Explanation: Green urine may result from biliverdin (oxidized bilirubin), Pseudomonas infection (pyocyanin pigment), or drugs such as methylene blue and amitriptyline. Careful history and laboratory tests are essential to distinguish pathological from drug-induced causes.

38. Red urine without RBCs on microscopy suggests:

• A) Hemoglobinuria
• B) Hematuria
• C) Pyuria
• D) Crystalluria
Answer: A) Hemoglobinuria
Explanation: Hemoglobinuria causes red urine with no intact RBCs on microscopy because free hemoglobin is filtered. Hematuria shows RBCs microscopically, pyuria shows pus cells, and crystalluria shows crystals. Myoglobinuria also produces red urine without RBCs and must be differentiated biochemically.

39. Which of the following is the most common cause of nocturia?

• A) Heart failure
• B) Chronic kidney disease
• C) Diabetes mellitus
• D) All of the above
Answer: D) All of the above
Explanation: Nocturia, frequent night urination, is common in heart failure (redistributed fluid), chronic kidney disease (impaired concentrating ability), and diabetes mellitus (osmotic diuresis). It may also occur physiologically in elderly due to reduced bladder capacity and altered circadian rhythm of ADH.

40. Urine with red fluorescence under Wood’s lamp is due to:

• A) Bilirubin
• B) Porphyrins
• C) Myoglobin
• D) Hemoglobin
Answer: B) Porphyrins
Explanation: Porphyrins excreted in urine fluoresce red or pink under Wood’s lamp (UV light), aiding diagnosis of porphyrias. Bilirubin does not fluoresce distinctly, myoglobin and hemoglobin alter color but not fluorescence. This test is used in screening for inherited or acquired porphyria disorders.

41. Which urine abnormality is most commonly seen in uncontrolled diabetes mellitus?

• A) Proteinuria
• B) Ketonuria
• C) Hematuria
• D) Chyluria
Answer: B) Ketonuria
Explanation: In uncontrolled diabetes mellitus, impaired glucose utilization leads to fat metabolism and ketone body excretion in urine. This produces fruity odor and increases urine acidity. Proteinuria occurs in nephropathy, hematuria in infections, and chyluria in lymphatic obstruction, not primarily diabetes.

42. Which factor most affects urine turbidity when left standing?

• A) Protein precipitation
• B) Phosphate precipitation
• C) Uric acid crystallization
• D) Bacterial multiplication
Answer: D) Bacterial multiplication
Explanation: Standing urine often turns turbid due to bacterial growth, which breaks down urea to ammonia, raising pH and precipitating phosphates. Protein and urates may cause initial cloudiness, but bacterial multiplication is the main factor in persistent turbidity.

43. A urine specimen showing red color but testing negative for blood on dipstick is most likely due to:

• A) Myoglobin
• B) Hemoglobin
• C) Porphyrins
• D) Drugs or food pigments
Answer: D) Drugs or food pigments
Explanation: Red urine with negative dipstick blood test suggests exogenous pigments like beetroot, rifampicin, or phenazopyridine. Myoglobin and hemoglobin yield positive dipstick heme reactions. Porphyrins cause reddish urine but usually test positive with special assays.

44. Which urinary finding suggests glomerular origin of hematuria?

• A) Bright red urine
• B) Cola-colored urine with RBC casts
• C) Milky urine with fat globules
• D) Green urine with pigments
Answer: B) Cola-colored urine with RBC casts
Explanation: Glomerular hematuria appears as cola-colored urine due to hemoglobin alteration and presence of dysmorphic RBCs and RBC casts. Bright red urine suggests lower tract bleeding, milky urine indicates chyluria, and green urine is often pigment-related.

45. Which factor increases urine specific gravity?

• A) Excess water intake
• B) Intravenous glucose infusion
• C) Glycosuria
• D) Diabetes insipidus
Answer: C) Glycosuria
Explanation: Glycosuria increases urine solute concentration, elevating specific gravity above 1.030. Excess water intake and diabetes insipidus dilute urine, lowering specific gravity. IV glucose infusion increases plasma glucose but does not directly affect urine unless renal threshold is exceeded.

46. Green foam on shaking urine is most characteristic of:

• A) Proteinuria
• B) Bilirubinuria
• C) Hematuria
• D) Ketonuria
Answer: B) Bilirubinuria
Explanation: Bilirubin in urine produces yellow-green coloration. On shaking, it forms stable green foam, distinguishing it from proteinuria (white foam). Hematuria and ketonuria alter color and odor, but not foam characteristics. This test helps diagnose obstructive jaundice.

47. Which physical characteristic of urine provides information about hydration status?

• A) Odor
• B) Volume
• C) Color
• D) Turbidity
Answer: C) Color
Explanation: Urine color reflects hydration: pale or nearly colorless urine indicates overhydration, while dark yellow urine suggests dehydration due to concentrated urochrome. Odor varies with metabolic conditions, volume is multifactorial, and turbidity depends on crystals or cells, not hydration alone.

48. Which abnormality causes urine to have a rancid odor?

• A) Tyrosinemia
• B) Cystinuria
• C) MSUD
• D) Phenylketonuria
Answer: A) Tyrosinemia
Explanation: In tyrosinemia, metabolic defects in tyrosine catabolism lead to accumulation of byproducts giving urine a rancid, cabbage-like odor. Cystinuria produces sulfur odor, PKU causes mousy odor, and MSUD gives maple syrup odor. Recognizing odors can help identify inborn errors of metabolism.

49. Which factor causes normal urine to become alkaline on prolonged standing?

• A) Uric acid precipitation
• B) Bacterial urease activity
• C) Bilirubin oxidation
• D) Protein breakdown
Answer: B) Bacterial urease activity
Explanation: Bacteria produce urease, which hydrolyzes urea into ammonia, raising urine pH to alkaline. This predisposes to phosphate precipitation and turbidity. Uric acid and protein breakdown influence other characteristics but not alkalinization. Bilirubin oxidation alters color but not pH.

50. Which physical examination finding indicates presence of bile salts?

• A) Dark urine
• B) Green foam test
• C) Milky turbidity
• D) Fruity odor
Answer: B) Green foam test
Explanation: Bile salts lower urine surface tension, forming stable yellow-green foam when shaken. This indicates cholestasis or obstructive jaundice. Dark urine alone is nonspecific, milky turbidity suggests chyluria, and fruity odor points to ketonuria, not bile salts.

51. Which condition produces dark red urine that remains red after centrifugation?

• A) Hematuria
• B) Hemoglobinuria
• C) Pyuria
• D) Phosphaturia
Answer: B) Hemoglobinuria
Explanation: In hemoglobinuria, urine remains uniformly red even after centrifugation, as hemoglobin stays dissolved in supernatant. In hematuria, RBCs settle leaving clear supernatant. Pyuria makes urine turbid, while phosphaturia causes cloudiness that clears on acidification.

52. Which urinary change is commonly observed in starvation?

• A) Proteinuria
• B) Hematuria
• C) Ketonuria
• D) Bilirubinuria
Answer: C) Ketonuria
Explanation: Starvation forces body to metabolize fat, producing ketone bodies that are excreted in urine. This causes fruity odor and acidic pH. Proteinuria occurs in renal disease, hematuria in bleeding disorders, and bilirubinuria in liver or bile duct disease.

53. The normal odor of urine is described as:

• A) Ammoniacal
• B) Aromatic
• C) Fruity
• D) Putrid
Answer: B) Aromatic
Explanation: Normal urine has a faint aromatic odor due to volatile organic compounds. When left standing, bacterial decomposition of urea produces ammoniacal odor. Fruity odor arises from ketonuria, while putrid odor suggests infection or pus. Odor changes are important clinical indicators.

54. Which factor does NOT influence urine color physiologically?

• A) Hydration
• B) Diet
• C) Medications
• D) RBC casts
Answer: D) RBC casts
Explanation: Hydration, diet, and drugs alter urine color physiologically. RBC casts, however, indicate renal pathology and are not normal. For example, beetroot gives reddish urine, rifampicin orange, while hydration alters urochrome concentration. Presence of RBC casts suggests glomerulonephritis.

55. Smoky brown urine in a patient with edema and hypertension most likely indicates:

• A) Nephrotic syndrome
• B) Acute glomerulonephritis
• C) Renal stones
• D) Hemoglobinuria
Answer: B) Acute glomerulonephritis
Explanation: Acute glomerulonephritis typically presents with smoky brown urine due to hemolyzed RBCs, along with edema and hypertension. Nephrotic syndrome shows proteinuria with frothy urine, renal stones cause hematuria, and hemoglobinuria produces uniformly red-brown urine without RBCs.

56. Urine that turns purple in catheter bags is due to:

• A) Bilirubin oxidation
• B) Indicanuria
• C) Porphyria
• D) Myoglobinuria
Answer: B) Indicanuria
Explanation: Purple urine bag syndrome occurs when bacterial breakdown of tryptophan produces indigo and indirubin pigments. It is seen in elderly catheterized patients with urinary tract infection. Bilirubin causes greenish urine, porphyria produces red, and myoglobinuria gives brown urine.

57. Which urine physical property is most affected in diabetes insipidus?

• A) Color
• B) Odor
• C) Specific gravity
• D) Turbidity
Answer: C) Specific gravity
Explanation: Diabetes insipidus leads to excretion of large volumes of dilute urine with very low specific gravity (<1.005). Color is pale but nonspecific, odor usually normal, and turbidity is absent. Specific gravity measurement is diagnostic in differentiating DI from other causes of polyuria.

58. Which physical urine change is common in urinary tract infections?

• A) Fruity odor
• B) Milky turbidity
• C) Cola color
• D) Blackening on standing
Answer: B) Milky turbidity
Explanation: Urinary tract infections often cause turbid, milky urine due to presence of pus cells, bacteria, and debris. Fruity odor indicates ketonuria, cola-colored urine suggests glomerulonephritis, and black urine occurs in alkaptonuria, not UTI.

59. Red urine that clears with heating suggests:

• A) Hematuria
• B) Phosphaturia
• C) Uric acid crystalluria
• D) Urate crystalluria
Answer: D) Urate crystalluria
Explanation: Urates precipitate in acidic urine on cooling, giving red to pink turbidity. Heating dissolves them, clearing the urine. Hematuria and hemoglobinuria are unaffected by heating, phosphates clear with acidification, not heat. This test helps differentiate benign urates from pathological causes.

60. Which urine abnormality is commonly seen in obstructive uropathy with infection?

• A) Colorless urine
• B) Greenish, foul-smelling urine
• C) Cola-colored urine
• D) Milky chyluria
Answer: B) Greenish, foul-smelling urine
Explanation: In obstructive uropathy complicated by infection, urine may appear green due to bacterial pigments and emit foul odor. Pseudomonas infection is a common cause. Cola-colored urine occurs in glomerulonephritis, milky urine in chyluria, and colorless urine in diabetes insipidus.

61. What is the normal pH range of freshly voided urine?

• A) 2.0–4.0
• B) 4.5–8.0
• C) 8.5–9.5
• D) 10–12
Answer: B) 4.5–8.0
Explanation: Fresh urine is usually slightly acidic due to metabolic activity, with a pH range of 4.5–8.0. Diet and systemic acid-base status influence it. High-protein diets lower pH, while vegetarian diets increase alkalinity. Extremely alkaline or acidic values may indicate infection, renal tubular disorders, or systemic acid-base disturbances.

62. Which method is commonly used for routine determination of urine pH?

• A) Flame photometry
• B) Litmus paper
• C) pH indicator strips
• D) Potentiometric titration
Answer: C) pH indicator strips
Explanation: pH indicator strips impregnated with chemical indicators are most commonly used in routine urinalysis. They provide quick, reliable, and semiquantitative results. Potentiometric pH meters are more accurate but used in specialized laboratories. Litmus paper is less specific. Urine pH helps in diagnosing systemic metabolic disorders and monitoring renal function.

63. Which urinary condition produces a persistent alkaline pH?

• A) Diabetic ketoacidosis
• B) Starvation
• C) Urinary tract infection with urea-splitting bacteria
• D) Lactic acidosis
Answer: C) Urinary tract infection with urea-splitting bacteria
Explanation: Urease-producing bacteria like Proteus and Klebsiella hydrolyze urea to ammonia, raising urine pH. This persistent alkalinity favors precipitation of phosphate and magnesium ammonium phosphate (struvite) crystals, leading to stone formation. Acidic pH is more common in metabolic acidosis and starvation states due to ketone and acid excretion.

64. Which factor lowers urine pH?

• A) Vegetarian diet
• B) High-protein diet
• C) UTI by Proteus
• D) Alkalosis
Answer: B) High-protein diet
Explanation: High-protein diets produce increased acid load from metabolism of sulfur-containing amino acids, leading to lower urine pH. Conversely, a vegetarian diet increases urinary alkalinity due to higher intake of alkaline salts. UTI with Proteus also alkalinizes urine, while alkalosis raises urinary pH to compensate systemic balance.

65. What is the significance of persistently acidic urine?

• A) Suggests bacterial infection
• B) Indicates systemic acidosis or starvation
• C) Implies vegetarian diet
• D) Suggests renal tubular acidosis type II
Answer: B) Indicates systemic acidosis or starvation
Explanation: Persistent acidic urine is a compensatory mechanism for metabolic acidosis, starvation, or diabetes mellitus. The kidneys excrete more hydrogen ions and ammonium to maintain systemic acid-base balance. In renal tubular acidosis, however, kidneys fail to acidify urine despite systemic acidosis, producing paradoxically alkaline urine.

66. What is the normal urine volume per 24 hours in adults?

• A) 100–300 mL
• B) 400–600 mL
• C) 800–2000 mL
• D) 2500–4000 mL
Answer: C) 800–2000 mL
Explanation: Average daily urine output in healthy adults is 800–2000 mL, depending on fluid intake, activity, and metabolism. Less than 400 mL/day indicates oliguria, while more than 2500 mL/day is polyuria. Abnormalities in urine volume provide essential diagnostic clues in systemic and renal pathologies.

67. What condition is associated with polyuria?

• A) Acute glomerulonephritis
• B) Congestive heart failure
• C) Diabetes mellitus and diabetes insipidus
• D) Shock
Answer: C) Diabetes mellitus and diabetes insipidus
Explanation: Polyuria (excessive urine output) occurs in uncontrolled diabetes mellitus due to osmotic diuresis by glucose and in diabetes insipidus due to ADH deficiency or resistance. Other causes include excessive fluid intake, hypercalcemia, and chronic renal failure. Oliguria and anuria occur in heart failure, shock, and severe renal disease.

68. Oliguria is defined as urine output less than:

• A) 200 mL/day
• B) 400 mL/day
• C) 800 mL/day
• D) 1000 mL/day
Answer: B) 400 mL/day
Explanation: Oliguria is defined as urine output less than 400 mL/day in adults. It occurs in conditions like dehydration, prerenal azotemia, acute glomerulonephritis, and shock. Severe reduction (<100 mL/day) is termed anuria, commonly seen in complete urinary obstruction, renal shutdown, or severe circulatory collapse.

69. Anuria refers to urine output less than:

• A) 50 mL/day
• B) 100 mL/day
• C) 200 mL/day
• D) 400 mL/day
Answer: B) 100 mL/day
Explanation: Anuria is defined as urine output less than 100 mL/day in adults. It is a medical emergency often caused by bilateral renal obstruction, acute tubular necrosis, or severe circulatory failure. Prompt recognition and treatment are crucial to prevent uremia and systemic complications.

70. Which factor may cause functional oliguria?

• A) Renal calculi
• B) Shock and dehydration
• C) Acute tubular necrosis
• D) Bilateral ureteric obstruction
Answer: B) Shock and dehydration
Explanation: Functional oliguria results from decreased renal perfusion due to circulatory disturbances like shock, dehydration, or congestive heart failure. It is not due to structural renal damage. Obstructive and renal parenchymal causes also produce oliguria, but functional oliguria is reversible once perfusion is restored.

71. What is the term for involuntary passage of urine?

• A) Dysuria
• B) Nocturia
• C) Incontinence
• D) Enuresis
Answer: C) Incontinence
Explanation: Incontinence refers to involuntary leakage of urine due to sphincter dysfunction, neurological disorders, or bladder instability. It can be stress, urge, or overflow type. Enuresis is involuntary urination during sleep, especially in children. Dysuria is painful urination, while nocturia is increased urination at night.

72. What does nocturia usually indicate?

• A) Urinary tract infection
• B) Congestive heart failure or chronic kidney disease
• C) Diabetes insipidus only
• D) Acute tubular necrosis
Answer: B) Congestive heart failure or chronic kidney disease
Explanation: Nocturia is defined as waking up frequently at night to urinate. It often indicates early renal impairment or congestive heart failure, where fluid redistributed during recumbency is excreted as urine. It can also be seen in diabetes mellitus, benign prostatic hyperplasia, and polyuric states.

73. What does the presence of frothy urine usually indicate?

• A) High glucose
• B) Proteinuria
• C) Ketones
• D) Bilirubin
Answer: B) Proteinuria
Explanation: Frothy urine occurs when proteins reduce surface tension, trapping bubbles in urine. Persistent frothiness is a hallmark of proteinuria, as seen in nephrotic syndrome, glomerulonephritis, or severe systemic diseases. While glucose and bilirubin can also alter urine appearance, froth is particularly associated with high protein content.

74. Which urine odor is characteristic of uncontrolled diabetes mellitus?

• A) Ammoniacal odor
• B) Fruity odor
• C) Musty odor
• D) Foul putrid odor
Answer: B) Fruity odor
Explanation: Fruity odor of urine results from ketone bodies, particularly acetone, in uncontrolled diabetes mellitus or starvation. Ammoniacal odor develops when urine is left standing or due to urea-splitting bacterial infection. Foul odor suggests severe UTI. Musty odor is sometimes observed in metabolic disorders like phenylketonuria.

75. Which physical property of urine is altered in dehydration?

• A) Odor
• B) Color and specific gravity
• C) pH
• D) Transparency
Answer: B) Color and specific gravity
Explanation: Dehydration leads to concentrated urine, giving it a darker color and higher specific gravity (>1.025). pH and odor are not specific indicators of hydration status. Specific gravity directly reflects solute concentration, hence it rises in dehydration and falls in conditions with dilute urine like diabetes insipidus.

76. Which type of urine sample is best for physical examination?

• A) Random sample
• B) First morning specimen
• C) Postprandial specimen
• D) Catheterized specimen
Answer: B) First morning specimen
Explanation: First morning urine is preferred for physical examination because it is the most concentrated, providing reliable assessment of color, specific gravity, and presence of abnormal substances. Random specimens may be diluted. Catheterized samples are invasive and reserved for sterile collection, while postprandial urine is mainly used for glycosuria detection.

77. Which factor can artifactually increase specific gravity of urine?

• A) Dehydration
• B) Glucosuria and proteinuria
• C) Starvation
• D) Low solute diet
Answer: B) Glucosuria and proteinuria
Explanation: Presence of large amounts of glucose or protein in urine increases specific gravity disproportionately, giving a falsely elevated impression of concentration. Dehydration also increases specific gravity, but physiologically. Correct interpretation requires correlating with clinical findings and urine osmolality for confirmation of concentrating ability.

78. Which condition is associated with persistently low specific gravity?

• A) Nephrotic syndrome
• B) Chronic pyelonephritis and diabetes insipidus
• C) Acute glomerulonephritis
• D) Shock
Answer: B) Chronic pyelonephritis and diabetes insipidus
Explanation: Persistently low specific gravity (<1.010) indicates inability of kidneys to concentrate urine, as seen in diabetes insipidus and chronic pyelonephritis. In contrast, acute glomerulonephritis and nephrotic syndrome may show higher specific gravity due to proteinuria. Shock causes oliguria with variable specific gravity.

79. What is isosthenuria?

• A) Specific gravity <1.005
• B) Specific gravity fixed around 1.010
• C) Specific gravity >1.030
• D) Rapid fluctuations in specific gravity
Answer: B) Specific gravity fixed around 1.010
Explanation: Isosthenuria is the excretion of urine with fixed specific gravity around 1.010, reflecting loss of renal tubular concentrating and diluting ability. It indicates severe renal tubular damage, often seen in chronic kidney disease and end-stage renal failure. This fixed value approximates the osmolality of plasma ultrafiltrate.

80. Which physical property of urine is most useful in detecting hydration status?

• A) Color
• B) pH
• C) Specific gravity
• D) Odor
Answer: C) Specific gravity
Explanation: Specific gravity is a direct indicator of urine concentration and reflects hydration status. In dehydration, specific gravity rises (>1.025), while in overhydration or diabetes insipidus, it falls (<1.005). Color also changes with hydration but is less precise. Odor and pH are not reliable markers for hydration.

81. Which urine sample is preferred for evaluating diurnal variation in volume?

• A) First morning specimen
• B) Random specimen
• C) 24-hour urine collection
• D) Postprandial specimen
Answer: C) 24-hour urine collection
Explanation: A 24-hour urine collection is the gold standard for evaluating total volume and diurnal variation. It helps in diagnosing polyuria, oliguria, and disorders of water balance. Random or spot samples may give misleading results. Proper collection and preservation are critical for accuracy.

82. What does cloudy urine usually indicate?

• A) Excess ketones
• B) Phosphate or urate crystals, pus, or bacteria
• C) Proteinuria
• D) Hemoglobinuria
Answer: B) Phosphate or urate crystals, pus, or bacteria
Explanation: Cloudy or turbid urine results from precipitation of crystals (urates, phosphates), presence of pus (pyuria), or bacteria. Fresh normal urine is usually clear. Protein and hemoglobin do not cause turbidity but alter color. Microscopic examination confirms the cause of cloudiness.

83. Milky urine is most commonly due to:

• A) Hematuria
• B) Lipiduria or chyluria
• C) Bacterial infection
• D) Excess bilirubin
Answer: B) Lipiduria or chyluria
Explanation: Milky urine may result from lipiduria in nephrotic syndrome or chyluria due to lymphatic obstruction from filariasis. Microscopic examination shows fat globules or chylomicrons. Bacterial infection causes turbidity, while hematuria produces red coloration.

84. What does urine with a musty odor suggest?

• A) Diabetes mellitus
• B) Phenylketonuria
• C) UTI
• D) Starvation ketosis
Answer: B) Phenylketonuria
Explanation: A musty or mousy odor is characteristic of phenylketonuria (PKU), an inherited metabolic disorder caused by deficiency of phenylalanine hydroxylase. Accumulated phenylalanine metabolites impart the odor. Fruity odor suggests diabetes, while ammoniacal odor suggests UTI.

85. Which urine abnormality is seen in obstructive jaundice?

• A) Deep yellow to brown urine with foam
• B) Fruity odor
• C) Low specific gravity
• D) Cloudy appearance
Answer: A) Deep yellow to brown urine with foam
Explanation: In obstructive jaundice, conjugated bilirubin is excreted in urine, producing dark yellow to brown coloration and persistent yellow foam on shaking. This differentiates it from normal froth. Fruity odor indicates ketonuria, and specific gravity changes depend on hydration.

86. What does smoky brown urine typically indicate?

• A) Myoglobinuria
• B) Glomerular hematuria
• C) Bile pigment
• D) Crystals
Answer: B) Glomerular hematuria
Explanation: Smoky or cola-colored urine is typical of glomerular bleeding, as in glomerulonephritis. Hemoglobin released from lysed RBCs is oxidized, producing brown coloration. Myoglobinuria also produces brown urine but without intact RBCs on microscopy.

87. In fresh urine, ammoniacal odor indicates:

• A) Contamination during collection
• B) Starvation ketosis
• C) UTI with urea-splitting organisms
• D) Dehydration
Answer: C) UTI with urea-splitting organisms
Explanation: Urease-positive bacteria (Proteus, Klebsiella) split urea into ammonia, imparting a strong ammoniacal odor to urine. Starvation ketosis gives fruity odor, while contamination or dehydration do not cause this characteristic smell.

88. What does excessive foamy urine persisting after standing suggest?

• A) Proteinuria
• B) Normal urine variation
• C) Hemoglobinuria
• D) Bilirubinuria
Answer: A) Proteinuria
Explanation: Persistent foamy urine is highly suggestive of proteinuria. Normal urine may produce transient froth, but persistent foamy bubbles indicate surface tension changes due to albumin. This is especially seen in nephrotic syndrome.

89. Normal urine odor is best described as:

• A) Fruity
• B) Foul
• C) Aromatic or faintly characteristic
• D) Musty
Answer: C) Aromatic or faintly characteristic
Explanation: Fresh normal urine has a faintly aromatic odor due to volatile acids and organic compounds. Decomposition of urine on standing produces an ammoniacal odor. Fruity, foul, or musty odors indicate pathological states.

90. What is the cause of high urine output in diabetes mellitus?

• A) Increased water intake
• B) Osmotic diuresis due to glucosuria
• C) ADH deficiency
• D) Low renal threshold
Answer: B) Osmotic diuresis due to glucosuria
Explanation: In uncontrolled diabetes mellitus, excess glucose in urine exerts an osmotic effect, preventing water reabsorption in renal tubules. This leads to polyuria with high specific gravity. Diabetes insipidus, in contrast, is due to ADH deficiency or resistance.

91. Which type of urine collection is required for accurate volume measurement?

• A) First morning urine
• B) Midstream urine
• C) 24-hour urine
• D) Random spot urine
Answer: C) 24-hour urine
Explanation: For accurate urine volume and quantitative biochemical analysis, a 24-hour collection is essential. It accounts for diurnal variation and provides reliable averages. Spot or first morning specimens are used for routine qualitative tests, not for exact volume estimation.

92. What does straw-colored urine indicate?

• A) Normal urine
• B) Jaundice
• C) Hematuria
• D) Dehydration
Answer: A) Normal urine
Explanation: Normal urine is pale yellow to straw-colored due to urochrome pigment. Variations occur with hydration and diet. Jaundice produces dark yellow or brown urine, hematuria gives red urine, and dehydration deepens yellow coloration.

93. What is the physical characteristic of urine in severe dehydration?

94. Which factor does NOT influence urine color?

• A) Pigments like urochrome
• B) Food and drugs
• C) Systemic disease
• D) Specific gravity only
Answer: D) Specific gravity only
Explanation: Urine color is primarily influenced by urochrome pigment, food substances, drugs, and disease states. Specific gravity affects transparency and concentration but is not a direct determinant of urine color.

95. What does red urine without RBCs on microscopy suggest?

• A) Hematuria
• B) Hemoglobinuria or myoglobinuria
• C) Bacterial infection
• D) Phosphaturia
Answer: B) Hemoglobinuria or myoglobinuria
Explanation: Red urine with absence of intact RBCs suggests free hemoglobin (in hemolysis) or myoglobin (in rhabdomyolysis). True hematuria will show RBCs under microscopy. Biochemical tests and clinical correlation are essential for differentiation.

96. Which urine appearance suggests nephrotic syndrome?

• A) Milky due to lipiduria
• B) Smoky brown
• C) Dark yellow with foam
• D) Fruity odor
Answer: A) Milky due to lipiduria
Explanation: In nephrotic syndrome, lipiduria occurs due to leakage of lipoproteins into urine. This produces a milky or opalescent appearance. Microscopy may reveal fat globules and oval fat bodies. Proteinuria also causes persistent foam in nephrotic urine.

97. What does pale urine with low specific gravity indicate?

• A) Dehydration
• B) Diabetes insipidus or overhydration
• C) Hematuria
• D) Jaundice
Answer: B) Diabetes insipidus or overhydration
Explanation: Very dilute urine with low specific gravity (<1.005) is typical of diabetes insipidus, where ADH deficiency impairs water reabsorption. It may also occur in excessive water intake. Dehydration causes concentrated dark urine.

98. Which color does rifampicin impart to urine?

• A) Red-orange
• B) Green
• C) Black
• D) Blue
Answer: A) Red-orange
Explanation: Rifampicin, an antitubercular drug, imparts a bright red-orange color to urine, tears, and sweat. This is harmless but important to recognize for patient reassurance. Other drugs like methylene blue cause green or blue urine, while melanuria can cause black urine.

99. Black urine on standing suggests which condition?

• A) Alkaptonuria
• B) Hematuria
• C) Biliary obstruction
• D) Lipiduria
Answer: A) Alkaptonuria
Explanation: In alkaptonuria, homogentisic acid is excreted and oxidizes on standing, turning urine black. This rare metabolic disorder results from homogentisic acid oxidase deficiency. Hematuria and jaundice cause red or dark urine but not black.

100. Which urine abnormality is diagnostic of rhabdomyolysis?

• A) Proteinuria
• B) Myoglobinuria
• C) Lipiduria
• D) Bacteriuria
Answer: B) Myoglobinuria
Explanation: Myoglobinuria occurs due to massive skeletal muscle breakdown in rhabdomyolysis, producing brown to red urine without RBCs on microscopy. Myoglobin is nephrotoxic and may cause acute renal failure. Proteinuria and bacteriuria are nonspecific, while lipiduria suggests nephrotic syndrome.