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

What is the correct nomenclature to describe a hematologic disorder with trisomy 21 in 6 cells and 14 cells that are normal?

1. 47,XY,+21?c[6]/46,XY[14]

2. 45,XY,-21?c[4]/46,XY[16]

3. 46,XY,+21[6]/47,XY[14]

4. 47,XX,+21?c[6]/46,XX[14]

The correct answer is: 47,XY,+21?c[6]/46,XY[14]

The correct answer presents the appropriate nomenclature for a hematologic disorder indicating an individual with two distinct cell populations: one population with trisomy 21, represented as "47,XY,+21?c[6]", and another population that is normal, represented as "46,XY[14]". In this nomenclature, "47,XY,+21" signifies that there are 47 chromosomes in total, including an additional chromosome 21, which corresponds to the presence of trisomy 21 in those 6 cells. The notation "46,XY" for the other 14 cells indicates a normal male karyotype without any extra chromosomes. The "?c" notation is used to distinguish the cells with abnormal karyotypes, while the bracketed numbers indicate the count of cells. Overall, this format accurately describes the chromosomal makeup of both populations, aligning with the conventions used in cytogenetic reporting to communicate complex karyotypic findings in an organized manner.