Answer to Question 1
ANS: B
The direct antiglobulin test detects antibodies present on the red blood cell (RBC) membrane. Because they are not present in hereditary spherocytosis, this test will be negative (normal). Red cell morphology ideally shows spherocytes (depending on the number present), the osmotic fragility is increased, and the reticulocyte count is increased.
Answer to Question 2
ANS: A
Hereditary spherocytosis has membrane protein deficiencies that result in an unsupported red cell membrane. This leads to a reduced surface area.