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

What tissue would be cultured next to rule out the presence of t(9;22) in a patient suspected of having CML?

1. Peripheral blood

2. Bone marrow

3. Lymph node

4. Skin biopsy

The correct answer is: Bone marrow

In the context of ruling out the presence of the t(9;22) chromosomal translocation, which is commonly associated with chronic myelogenous leukemia (CML), culturing bone marrow is the most appropriate approach. Bone marrow is not only a primary site of hematopoiesis but also contains a higher concentration of myeloid cells where the alterations associated with CML, such as the formation of the BCR-ABL fusion gene as a result of the t(9;22) translocation, may be more readily identifiable. While peripheral blood can also be used for cytogenetic analysis, bone marrow samples typically provide a richer and more representative cellular environment, especially in hematological malignancies. This is because in conditions like CML, leukemia cells often maintain a higher predominance in the bone marrow compared to peripheral blood, thereby increasing the likelihood of detecting the specific genetic aberration. Lymph nodes do not typically play a direct role in CML detection since this disease primarily originates in the bone marrow and not from lymphatic tissue. Skin biopsy would not be relevant at all in this scenario, as it does not provide any information pertinent to the myeloid lineage or the genetic markers associated with CML. Using bone marrow for culture