Pancytopenia is defined as?

• A. An abnormally reduced number of red blood cells.
• B. A deficiency of white blood cells only.
• C. An abnormally reduced number of all cellular components in the blood.
• D. An excess of platelets.

Answer: (C)

Pancytopenia means low counts across all three major blood cell lines: red blood cells, white blood cells, and platelets. This pattern points to bone marrow failure or suppression affecting production of all cellular components, rather than a deficit in a single line. Therefore the description “an abnormally reduced number of all cellular components in the blood” is the best fit.

The other options describe problems with only one blood component (anemia from reduced red cells; leukopenia from reduced white cells) or an excess of platelets (thrombocytosis), which do not capture the multi-lineage decrease characteristic of pancytopenia. Pancytopenia is commonly seen with conditions like aplastic anemia, marrow infiltration, or treatment effects such as chemotherapy, and it signals a broader marrow issue rather than a single-line problem.