This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
The most impoant example of a compensated hemolytic anemia becomes decompensated, is when: 
Select and explain. 
A. Infected with TB, B. Infected with parvovirus B19, C. Liver disease, D. Renal cell carcinoma
B: Infected with parvovirus B19
Answer: B: Infected with parvovirus B19 
Explanation: A patient with a hemolytic condition may present without anemia (Compensated hemolytic anemia) It becomes decompensated in Pregnancy Folate deficiency Renal failure (Interfering with adequate EPO production). Also in Acute infections- which depresses erythropoiesis. The most dramatic example is parvovirus B19 infection, which may lead to aplastic crisis. Ref: Harrison, E-18,P-873.