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.