Very Severe Aplastic Anemia

**Semantic type:** Disease or Syndrome

**Definition:** Aplastic anemia that is characterized by bone marrow (BM) cellularity less than 25% (or less than 50% if BM is comprised of less than 30% hematopoietic cells), and two or more of the following: absolute neutrophil count of less than 200 per microliter; platelet count of less than 20,000 per microliter; or an absolute reticulocyte count of less than 20,000 per microliter.

**Synonyms:** - VSAA