American Society for Clinical Pathology (ASCP) Technologist in Cytogenetics certification (ASCP CG) Practice Test

What procedure is LEAST likely to be informative for a patient with questionable leukemia and a low white cell count?

1. Bone marrow aspiration

2. PHA-stimulated blood culture

3. FISH analysis

4. Cytogenetic panel

The correct answer is: PHA-stimulated blood culture

The procedure that is least likely to be informative for a patient with questionable leukemia and a low white cell count is a PHA-stimulated blood culture. PHA (phytohemagglutinin) is a mitogen that stimulates lymphocyte proliferation. In the context of evaluating leukemia, high white blood cell counts are often anticipated, as leukemia is characterized by the overproduction of immature or abnormal blood cells. A low white cell count may indicate that the peripheral blood is not providing sufficient cellularity to demonstrate the abnormalities associated with leukemia. In cases where leukemic cells are scarce, the PHA-stimulated blood culture might not yield informative results, as the low baseline cell count can limit cell division and proliferation needed for effective analysis. On the other hand, bone marrow aspiration is more likely to provide valuable diagnostic information. It directly samples the bone marrow where leukemic cells may be more abundant. FISH analysis and cytogenetic panels are also vital because they can detect specific chromosomal abnormalities associated with various leukemias, which can be present even when the peripheral blood count is low.