Table 4 Limitations of carrier screening
From: A systematic analysis of online marketing materials used by providers of expanded carrier screening
Limitation (no. and percentage of providers that mentioned it; n = 18) | Illustrative quotes (provider, medium) |
|---|---|
Residual risk (11; 61%) | “[No] test can detect all possible mutations that could cause a disorder, so there is always a small chance (called a residual risk) of being a carrier even after a negative test result.” (Good Start Genetics, website text) |
“[It is] important to keep in mind that carrier screening is risk-reducing, not risk-eliminating. That means that even if you undergo testing for the most extensive panel, a full negative result does not completely guarantee that you are not a carrier for one of those conditions.” (Mount Sinai Hospital, information video voiceover) | |
“[A negative result] means that we did not detect any disease causing variants for which you were screened. While your risk for having a child with one of these conditions is significantly decreased, Horizon, like other carrier screens, does not screen for all possible variants.” (Natera, website text) | |
Does not test for all possible genetic disabilities (4; 22%) | “This analysis does not detect germline mosaicism, and does not rule out the presence of large chromosomal aberrations including deletions, insertions, and rearrangements, or mutations in regions or genes not included in this test, and possible inter/intragenic interactions between sequence variants.” (Integrated Genetics, website text) |
Limitations to analytic validity (3; 17%) | “[Discordant] results may occur due to bone marrow transplantation, blood transfusions, or other causes. In some cases, genetic variations other than those being tested may interfere with mutation detection, resulting in false negative or false positive results.” (Sequenom, website text) |
