A patient with anemia is found to have a low level of haptoglobin and a high level of lactate dehydrogenase. What is the most likely diagnosis?

A Hemolytic anemia due to glucose-6-phosphate dehydrogenase deficiency
B Hemolytic anemia due to autoimmune disorders
C Hemolytic anemia due to paroxysmal nocturnal hemoglobinuria ✓
D Hemolytic anemia due to microangiopathic hemolytic anemia

Explanation

Low haptoglobin and high lactate dehydrogenase levels are indicative of intravascular hemolysis, which is characteristic of paroxysmal nocturnal hemoglobinuria.

Source

Harrison's Principles of Internal Medicine
Hematology Hematology: Anemia Hematology: Anemia Hard MEDICAL Confidence: high