Which test is typically performed first to exclude parentage or paternity claims?

The most common test performed first to exclude parentage or paternity claims is ABO and Rh testing. This is because ABO blood group testing can quickly determine the blood type of an individual, including the potential parent and child. By comparing the blood types of the alleged parent(s) with that of the child, it is often possible to exclude a person as the biological parent if their blood type is incompatible with the child's expected blood type based on inheritance patterns.

ABO and Rh testing serves as a preliminary step due to its simplicity and speed, allowing healthcare professionals to make initial assessments regarding parentage claims.

While DNA profiling offers highly accurate results regarding parentage and is the gold standard for resolving such claims, it is not typically the initial test performed due to its complexity and the time required to process and analyze samples. HLA typing is used for tissue matching rather than blood relationship determination, and the Coombs test detects antibodies that could cause hemolytic reactions and is not relevant for establishing parentage. Thus, ABO and Rh testing’s effectiveness and efficiency in initial assessments of parentage make it the first line of testing in such situations.