maternal contamination
Presence of maternal DNA in fetal samples that can lead to false-negative results in genetic testing. Critical quality control concern.
Full Definition
A technical complication in prenatal genetic testing where maternal cells or DNA contaminate the fetal sample, potentially masking fetal abnormalities and leading to false-negative results. This contamination is particularly problematic in amniocentesis and chorionic villus sampling procedures, where maternal tissue may inadvertently be included in the sample. The presence of normal maternal DNA can dilute or mask abnormal fetal genetic material, especially in cases of mosaicism or when testing for specific mutations. Modern laboratories employ various techniques to detect and account for maternal contamination, including short tandem repeat analysis and sex chromosome markers.
Usage
Usage note: Distinguish clearly from other forms of sample contamination in laboratory reports.
In Context
- "The laboratory detected significant maternal contamination in the CVS sample, requiring repeat testing." — Laboratory quality control report
- "Protocols must include maternal contamination screening to ensure accurate fetal genetic analysis." — Laboratory standard operating procedures