PILOT-STUDIES FOR PROFICIENCY TESTING USING FLUORESCENCE IN-SITU HYBRIDIZATION WITH CHROMOSOME-SPECIFIC DNA PROBES - A COLLEGE-OF-AMERICAN-PATHOLOGISTS AMERICAN-COLLEGE-OF-MEDICAL-GENETICS PROGRAM

Fluorescence in situ hybridization using chromosome-specific DNA probe s is rapidly becoming part of clinical laboratory practice for certain congenital and neoplastic disorders. Current legislation requires pro ficiency testing for clinical laboratory studies. To evaluate the effi cacy of fluorescence in situ hybridization proficiency testing, we inv ited 19 representative institutions to participate in three pilot stud ies. One study used probes for the X and Y chromosomes to evaluate met aphase spreads and interphase nuclei. Another study used probes for bc r and abl to detect bcr/abl fusion in interphase nuclei in chronic mye logenous leukemia. The third study used a D22S75 probe to detect micro deletions in metaphase spreads from a patient with velocardiofacial sy ndrome. The results of these studies demonstrate that proficiency test ing with fluorescence in situ hybridization is attainable using either metaphase or interphase preparations, and that either microscope slid es or fixed cell pellets are suitable.