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How DNA Home Testing Kits Work – What Happens After The Swab

A DNA home testing kit allows individuals to collect the DNA samples that need to be tested and send them to a lab, after which they wait for the results after a couple of business days. These kits are most commonly used for testing a child’s paternity, but they could also be used to test one’s ancestry or identify their background.

When you purchase the kit, you’ll notice that it comes with three sets of swabs, which are similar to Q-tips. These swabs are used to collect the DNA sample by swabbing the inside of the cheeks of the individual(s) whose DNA is to be tested. After swabbing, place the swab in an envelope which is marked with the person’s name in order to avoid confusion. After collecting all the samples that you need, mail them to the lab and wait for the results.

When the samples get to the lab, each sample is divided into two, so that two separate tests are done on the same person’s DNA. This is usually to make sure that the results attained are conclusive. The DNA is then extracted and purified. What is extracted is then added to a chemical mixture to cause a reaction. This reaction targets 16 specific spots in the DNA- 15 of which are known to be the ones that vary the most between individuals, and one which determines the sex of the individual. All these areas are then duplicated millions of times. After this, the duplicates are then separated at specific locations and sorted out according to size. A DNA profile is then created from the code derived at these locations. This profile is like a bar-code, and is unique to every individual.

If the test ordered was a paternity test, then the child’s DNA profile is compared with that of the alleged father’s. The common factors in the profile are what determines the relationship between the individuals. A statistical analysis is then done on the profiles, and the higher the number of common factors, the closer the relationship. If the individual tested happens to be the child’s father, then the probability will be indicated as 99.9%.

After the test is done, the results are given to the individual whose name appears in the consent form which is filled out from the kit. The DNA samples and extracts in the lab are then destroyed.

Since the collection of samples is done at home, it’s important to be careful so as to not contaminate them. The first rule is to make sure that you don’t eat or drink anything for at least an hour before collecting the samples. Food usually masks the DNA and you’ll have to recollect the samples and wait longer for your results. Also, never touch the tips of the swabs, drop them or mix up the samples.

Although convenient, DNA home testing kits are as trustworthy as the individuals using them, and should therefore be handled with care. To avoid any mishaps, make sure you read the instructions on the kit before using it.

  • Updated September 9, 2017
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