2. Does my risk of being a carrier vary depending on my ancestry?
Generally, the frequency of CF carriers is highest in Caucasians (1/25), about half that in people with Hispanic Caucasian or African ancestry, and about half that again in people of Asian ancestry. Some ethnic groups, such as individuals of Eastern European Jewish descent, may show CF confined to a very limited number of mutations. Since the ancestry of the U.S. population is becoming increasingly blended, the historical data and statistical risks are changing. Quoted risks based on ancestry are estimates, and the risk for individuals of mixed ancestry may be unknown. Some families may also carry the additional risk of specific rare mutations within their family tree.
3. What are the advantages of the DNA-based blood test over other CF screening tests?
Generally, the DNA-based mutation test is much more specific than other screening tests, which may yield abnormal results for non-CF reasons. Also, these other screening tests may be restricted as to when they can be applied (for example, newborns cannot be tested with sweat chloride until about two months of age). Furthermore, DNA-based testing is the only reliable means of identifying carriers of CF mutations, and it is in this capacity that the testing is being most widely applied.
4. Do states require or offer newborn screening for CF? Do I need to request it?
Every state's newborn screening program includes a test for CF so you will not need to request it. The method used may vary, with some states performing only a test to determine the blood level of a chemical called immunoreactive trypsinogen (IRT) and others performing both an IRT and the DNA-based mutation test when the IRT level is high.
This article was last reviewed on January 17, 2013. | This article was last modified on January 17, 2013.
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