Even if no one in your family has CF and even if you already have children without CF, you could be a carrier of CF. In various populations, the table below shows the frequency of CF carriers and the detection rates of the carrier testing. If someone in your family has CF or is a carrier, your risk will be higher than the risks listed below. Carrier testing requires a small sample of blood and the results take several weeks.
The testing is highly accurate. However, a negative test result means that a small chance of being a carrier remains. This is because current testing does not include rare mutations, which may be present and lead to the occurrence of CF in a child. Thus, if only one member of a couple is found to be a carrier, while the other tests negative, it is still possible for a child to be affected. However, that chance is quite small. Genetic counseling would be available and the new risk can be calculated. In some cases, further testing may be warranted.
If a pregnancy is already underway as you are deciding about testing, it is best to test both partners at the same time because of the length of time it takes for results, usually several weeks. If CF testing shows both parents are carriers, genetic counseling will be recommended to provide you with more information about CF, as well as to discuss your prenatal options. You may also request genetic counseling prior to having any testing.