Getting a paternity test involves collecting DNA samples (usually a painless cheek swab) from the child and the potential father, then sending those samples to a lab for comparison. The process differs depending on whether you need results for personal knowledge or for legal purposes like child support or custody. Here’s how each option works and what to expect.
At-Home vs. Legal: Two Different Processes
The type of paternity test you need depends entirely on what you plan to do with the results. An at-home test (sometimes called a “peace of mind” test) gives you an answer, but it can’t be used in court. A legal test produces court-admissible results that hold up in custody disputes, child support cases, immigration proceedings, birth certificate changes, and estate matters. The DNA analysis itself is identical in both cases. The difference is paperwork and supervision.
For an at-home test, you order a kit online or buy one at a pharmacy, swab the cheeks of the child and potential father at home following the kit instructions, and mail the samples back to the lab. No one verifies who provided the samples.
A legal test requires what’s called a “chain of custody.” That means a trained professional at a certified collection facility watches each person provide their sample, checks government-issued photo ID, photographs participants, and documents the entire process so there’s no question about whose DNA was tested. AABB-accredited labs (the industry standard for relationship testing in the U.S.) require this chain of custody for any results intended for legal use. You cannot convert an at-home test into a legal one after the fact.
How Samples Are Collected
The standard sample is a buccal swab: a long cotton swab rubbed along the inside of the cheek to collect cells containing DNA. It takes about 30 seconds per person and is painless, making it safe for newborns and adults alike. Buccal swabs and blood samples produce results with the same degree of accuracy, but cheek swabs are used in the vast majority of tests because they’re simpler and noninvasive.
Most tests require samples from the child and the alleged father. Including the mother’s sample isn’t mandatory but can strengthen the statistical analysis. If the alleged father is unavailable or deceased, testing may still be possible using stored biological specimens collected by a coroner’s office, or by testing DNA from close biological relatives like parents or siblings of the alleged father. These cases typically require coordination between the lab and other agencies.
Testing During Pregnancy
You don’t have to wait until the baby is born. A noninvasive prenatal paternity test (NIPP) can be performed as early as the eighth week of pregnancy. It works because small fragments of the fetus’s DNA circulate in the mother’s bloodstream. A provider draws blood from the mother and takes a cheek swab from the potential father, then the lab isolates the fetal DNA from the blood sample and compares it to the father’s.
This test carries no risk to the pregnancy since it only requires a standard blood draw from the mother. Older methods of prenatal paternity testing involved procedures like amniocentesis, which carried a small risk of miscarriage. The blood-based NIPP test has largely replaced those approaches. The tradeoff is cost: prenatal tests typically run $1,000 to $2,500 or more, compared to $100 to $300 for a postnatal at-home kit.
What the Lab Actually Analyzes
Paternity labs compare specific locations on DNA called genetic markers. A child inherits half their DNA from each biological parent, so at every marker tested, one version should match the mother and one should match the biological father. If the tested man’s DNA consistently matches at every marker, he is included as the father. If it doesn’t match at multiple markers, he is excluded.
The number of markers tested has increased over the years. Early tests in the 2000s examined 8 to 11 markers. Current commercial testing kits analyze at least 21 markers, following updated FBI standards for the national DNA database (CODIS). More markers mean higher statistical confidence and fewer edge cases, particularly in situations where two potential fathers are closely related to each other.
When a man is included as the biological father, results are reported as a “probability of paternity,” typically 99.9% or higher. When he is excluded, the result is 0%. The test is essentially definitive in either direction.
How Long Results Take
Most labs return results within 3 to 5 business days after receiving the samples. Some offer rush processing for an additional fee. Prenatal tests can take slightly longer because isolating fetal DNA from a maternal blood sample requires more complex analysis. Legal tests may also take a bit longer due to the additional verification steps, though the lab processing time itself is similar.
What It Costs
At-home paternity test kits range from $100 to $300. This usually covers the kit, lab processing, and results. Some kits sold at pharmacies advertise a lower shelf price but charge a separate lab fee when you mail in the samples, so check the total cost before purchasing.
Legal paternity tests cost $400 to $800 or more, reflecting the added cost of supervised collection at a certified facility and the chain-of-custody documentation. If a court orders the test, the court may specify which lab to use and who pays.
Prenatal tests are the most expensive option at $1,000 to $2,500, largely because the lab work is more technically demanding. Insurance rarely covers paternity testing of any kind.
Steps to Get Started
- For personal answers: Order an at-home kit from an AABB-accredited lab online or pick one up at a pharmacy. Follow the instructions to swab each person’s cheek, register the kit on the lab’s website, and mail the samples in the prepaid packaging. Results arrive by email or secure online portal.
- For legal purposes: Contact an AABB-accredited lab directly to schedule appointments at a certified collection facility. Each participant (child, alleged father, and optionally the mother) will need to bring valid photo ID. The facility handles all sample collection and documentation, then ships everything to the lab under chain of custody.
- During pregnancy: Talk to your OB-GYN or contact a lab that offers NIPP testing. The mother’s blood draw can be done at a clinic or lab, and the potential father provides a cheek swab. Some labs handle prenatal tests as legal tests with full chain of custody if you anticipate needing the results in court.
State-Specific Rules to Know
A few states restrict who can order DNA testing. New York, for example, requires a physician’s order or court order before a paternity test can be performed. You cannot simply buy a kit off the shelf in New York the way you can in most other states. If you live in a state with restrictions, a legal testing lab can walk you through the requirements when you call to set up the test.