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When samples for a paternity test are collected , the DNA carried within the cheek swabs could become contaminated before they are sent to the lab. To prevent this from happening, here are a few tips for you to follow when collecting samples.

1. Don’t eat or drink, smoke, brush your teeth, etc.

Avoid eating, drinking or putting anything else in your mouth that can affect the test for at least one hour before doing the cheek swab collections. There is a chance that this foreign matter can mask the DNA, making it unusable for paternity tests. If this is the case, the lab will catch it and you’ll be notified (so there is no chance that your final results will be affected by it). If this happens, re-collections are completed one time at no cost to you. This means you’ll wait longer before you get your paternity test results, so it’s best to follow this guideline the first time!

2. Cross-contamination

Swabs may become contaminated by contact with another person’s DNA, perhaps by someone who is collecting the sample. This can happen by someone inadvertently handling the tips of the swab or dropping the swab. According to Dr. Donna Housley, IDENTIGENE lab director, ‘Sometimes the swabs are contaminated because people mix up the envelopes and put swabs from 2 different people in the same envelope, which is quite common.” So handle swabs with care and be sure to follow all package instructions carefully.

3. Blood transfusion or bone marrow transplant

If a participant has ever had a bone marrow transplant or a recent blood transfusion, the profile could be contaminated because we see two profiles from one individual when we amplify the DNA. Please make a note of the procedure you’ve had on the form when you submit it to the lab. If we determine it is affecting results, we will notify you.

4. When submitting DNA samples for paternity testing, avoid the original plastic packaging

Something else you want to avoid is placing the DNA collection swabs back into the plastic wrapper it originally arrived in. You want to place the samples directly into the paper envelope provided in the IDENTIGENE DNA collection kit, as noted in the instructions.

5. Mailing wet envelopes

Keep in mind collection envelopes may become wet because saliva may affix itself to the cheek cells that are needed to extract the DNA. If this happens, lay the sample envelope down on a clean counter and let them air-dry at room temperature. Sometimes when wet sample envelopes are mailed, they rip and this can contaminate all of the samples, including other participants’.

Follow these tips and all of the other instructions included inside of the IDENTIGENE DNA collection kit and your samples will most likely arrive at our laboratory ready for paternity testing, and you will receive your results on time. Now that you have sent your samples to IDENTIGENE, learn how to receive your results.

Follow us on Facebook and Twitter! If you have questions about paternity tests or other DNA testing services, please contact our Client Support Center at 888-404-4363, Mon-Fri from 9 AM to 6 PM Eastern Time. Our friendly, expert representatives are ready and happy to help. Get answers anytime by visiting our Help Center.

After DNA samples arrive at the laboratory, IDENTIGENE paternity test results are released in two business days. And they may not always be what are expected!

Sometimes when results of DNA testing show 0% probability, meaning the alleged father is not the biological father, there are some loci (or markers) in the report that do match between the alleged father and child. Participants may not understand why this occurs in DNA testing if the two participants aren’t related, so here’s a quick overview of how this happens.

Basics of a DNA Paternity Test

In paternity testing we generate DNA profiles using Polymerase Chain Reaction (PCR) process. PCR is the process of taking a small piece of DNA and making many enlarged copies so it can be measured for a paternity test. In the DNA profile analysts look at 15 specific loci or markers (location on the DNA chromosome for a gene) which are then reported on the DNA test results. The profiles are compared for all participants to determine if the alleged father and child match at all 15 markers or locations. Because the child gets 50% of its DNA from the biological father and %50 from the mother, there must be a match at all loci for the alleged father to be considered the biological father. If there are any mismatches, then the alleged father will be excluded, even if there are a few matches.

Loci Matches on Paternity Tests

A few positive matches can happen in DNA paternity testing because there are specific markers that are common among the population. When you look at the profiles on a paternity test, and there are some matches, this does not necessarily mean the participants are related. Each matching loci between the alleged father and child is calculated into a paternity index which measures the strength of a genetic match. This indicates how common that marker is in the population. Sometimes markers are very common so people that are not related may match at certain locations.

As stated above, in order to be a biological parent there must be a match at each location (with the rare exception of one mutation, which is a change in a gene passed from parent to child). If a possible mutation is identified, additional markers will be tested.

This is why you may have some locations that match on a paternity test but paternity test results nevertheless indicate the alleged father is not the biological father.

How do DNA Samples for Paternity Testing become Contaminated?

He’s Not the Biological Father? Why are there Matches in the Paternity Test?

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