A 20-year-old woman with acute hemolytic anemia has a hematocrit of 25% (normal 45%) and a reticulocyte count of 12%. Her corrected reticulocyte percentage is closest to:

• A 2.5%, indicating inadequate marrow response
• B 6.7%, indicating an appropriate marrow response ✓
• C 12%, indicating no correction needed in young adults
• D 24%, indicating extreme erythroid hyperplasia

Explanation

Corrected reticulocyte percentage = observed reticulocyte percent x (patient hematocrit / normal hematocrit) = 12 x (25/45) = 6.7%. Because the raw count is diluted by the falling red cell mass, it must be adjusted before judging marrow output. A corrected value above 2 to 3% indicates an appropriate erythropoietic response to anemia, as expected in hemolysis with adequate iron stores and renal function. Values below 2% would suggest hypoproliferation or marrow failure such as aplastic crisis.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.