Carrier screening for cystic fibrosis in US genetic testing laboratories: a survey of laboratory directors.

Initial guidelines for cystic fibrosis (CF) carrier screening were issued in 2001 by the American College of Medical Genetics and the American College of Obstetricians and Gynecologists and updated in 2004. It is unknown how these guidelines have influenced laboratory practice. This study examined the uptake of two components of these guidelines for CF screening in genetic testing laboratories. A survey of directors of US genetic testing laboratories was conducted. Of 190 respondents, 178 answered questions about CF testing. Nearly half (49%) performed some type of DNA testing for CF; most of these (92%) performed CF carrier screening. Ten percent used a 23-mutation panel for CF screening. The results of 5T tests were reported as a reflex test by 79% of laboratories, while 8% always returned 5T results and 7% never returned them. Seven percent of laboratories adopted both guidelines, 80% adopted one of the two guidelines, and 13% had not adopted either recommendation, suggesting that factors other than clinical guidelines may influence laboratories' CF screening practices. Further studies are needed to determine whether the adoption of CF screening guidelines has significant clinical or economic effects on population-based CF screening programs.