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Choosing a DNA Testing Laboratory DNA testing is a complicated process that must be performed by qualified, highly experienced scientists adhering to strict laboratory standards. The following are some aspects of DNA testing that you might wish to examine when choosing a DNA laboratory.
False Positive (Inclusion) Results
False positive results occur when the testing standards a laboratory uses is not stringent enough to give conclusive results. In such cases, a paternity test may result in a false inclusion (give the result that the tested man is the father even though he is not). Some laboratories have a lower standard for the probability of paternity—they take a 99% probability to be an inclusion. However, GeneMatch considers this probability too low to be conclusive. A 99% probability means that there are, statistically, a large number of other males in the population (1 in 100) who could be tested and give the same positive result as the tested alleged father. Laboratories who stop testing at 99% and consider the test to be conclusive are not doing their best to ensure reliable results. They may be trying to save on time and money by testing fewer locations on the DNA. GeneMatch takes the responsibility of testing until we get reliable and conclusive results. We test at least 16 markers (16 different DNA locations), which typically yields conclusive inclusion results of 99.99% and higher. In complicated genetic situations, we are able to perform an extended testing battery of up to 24 markers to ensure accurate, reliable results.
False Negative (Exclusion) Results
A false exclusion is a result in which the tested man is not considered to be the biological father. False exclusions are a common result of sample mix-ups or sample contamination in the laboratory. GeneMatch uses several safeguards to eliminate such errors:
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Dual-testing: When samples arrive in the laboratory, each person’s sample is properly recorded in the database, then divided into two so that two teams can perform the DNA test on the samples independently. After the testing process, the results from the two teams are compared to verify if they match. This crosschecking procedure assures the laboratory that all samples were tested correctly. |
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Advanced robotics: Many of the sample preparation and handling steps are performed by automated processors, ensuring precise and efficient sample processing and further eliminating the chance for cross-contamination and mixups. A laboratory technician monitors all processes to ensure testing accuracy. |
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Extended testing panel: Sometimes, mutations (unusual changes in the DNA) can result in one or two DNA locations not matching. While some laboratories might consider the test as an exclusion, GeneMatch continues testing more locations and performs extended analytical procedures until we have a conclusive, reliable result. Our Ph.D.s have the depth of experience needed to make accurate scientific judgments in such cases. |
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