A medical laboratory scientist performs fluorescence in situ hybridization (FISH) on interphase chromosomes using a probe to chromosome 21. In all cells examined, two signals were seen. These results are interpreted as:

Question

Quizplus · Accepted Answer

A normal result in FISH analysis for chromosome 21 should show two signals in interphase cells indicating that the patient has two copies of chromosome 21. If only one signal is seen, it would indicate a deletion of chromosome 21, and if three signals are seen, it would indicate a trisomy. The presence of a Philadelphia chromosome would require a different probe and analysis.

A Medical Laboratory Scientist Performs Fluorescence in Situ Hybridization (FISH)