Patients Who Have Had Invasive Procedures More Open to Carrier Testing


GRAPEVINE, TEX. — Patients referred for genetic testing are more likely to agree to carrier status testing if they already have accepted an invasive procedure.

A study of 3,131 patients referred for genetic testing found that individuals were more likely to accept cystic fibrosis carrier testing and were more likely to accept both CF and fragile X syndrome (FXS) carrier testing if they underwent an invasive procedure such as amniocentesis.

“Patients who underwent such a procedure were more than twice as likely to accept both screening tests, compared with patients who had declined invasive testing, said Amy Cronister, the study's lead author and regional manager of genetic services, Genzyme Genetics, Phoenix, Ariz.

This finding suggests that there may be specific populations of patients who generally tend to avoid genetic testing, and other populations for whom the concept of genetic testing is much more acceptable, she said at a meeting sponsored by the American College of Medical Genetics.

Overall, 33% of referrals agreed to carrier status testing for CF and 28% for FXS; 25% accepted CF and FXS testing; and 64% declined both. Significantly fewer (11%) accepted one test but declined the other.

There was no difference in carrier testing acceptance in patients referred because of maternal age and those with a positive maternal serum screening, Ms. Cronister said.

The study included patients referred for prenatal genetic counseling during a 22-month period because of maternal age, positive maternal serum screening, chemical exposure, or parental anxiety. The patients were offered both CF and FXS carrier testing on the basis of population screening only.

Because they would be more likely than the general population to accept CF and FSX screening, patients with a known or suggestive family history of either disease were excluded from the study.

Additionally, because CF risk is linked to ethnicity, only patients of white and Ashkenazi Jewish backgrounds, for whom the risk of being a CF carrier is 1 in 25 people, were included in the study.

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