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DNA Testing Basics: What It Can and Can't Tell You

Here's what a DNA test can actually tell you, and where its limits are.

  1. Direct-to-consumer (DTC) genetic testing

    A service where a consumer buys a kit directly, without going through a doctor, and mails in a saliva or cheek-cell sample to get information on things like regional ancestry, caffeine metabolism, or a tendency toward hair loss, based on specific genetic traits.

  2. Clinical genetic testing

    Testing carried out at a hospital or specialized testing facility, under a doctor's order, to check for the presence or predisposition to a specific genetic condition β€” used to help determine diagnosis and treatment direction.

  3. How paternity testing works

    Paternity testing uses the principle that a child inherits half of their DNA from each parent, confirming a parent-child relationship by comparing whether specific DNA regions (STRs) match.

  4. Forensic applications

    DNA can be extracted even from a tiny trace of blood or a hair left at a crime scene to help identify a person, and it's also used to help identify missing persons or unidentified remains.

  5. What to keep in mind when interpreting results

    Disease-risk information provided by DTC tests in particular is not a confirmed diagnosis but rather statistical, probability-based reference information β€” so rather than treating the result as final, it's best to consult a specialist for any further testing you might need if you're concerned.

  6. Protecting genetic information

    A DNA test result contains sensitive information about an individual and their family, so it's important to check a testing provider's level of privacy protection and how it uses your information before using its service.

  7. Regulation varies by country

    Regulations around what a direct-to-consumer genetic test is allowed to check for vary a great deal from country to country, and testing related to diagnosing an actual disease is generally required to go through a medical institution β€” always check your own country's current rules before using a DTC test.

What your DNA can reveal

A DNA test analyzes DNA extracted from saliva, blood, or similar samples to provide information on a range of things β€” ancestral origin, a genetic predisposition toward a certain condition, or a parent-child relationship. But reliability and appropriate use vary a great deal depending on the purpose and type of test, so it's important to understand what each kind of test can and can't tell you before relying on it.

Some genetic tests check for chromosome abnormalities, too

Among genetic tests, some specifically check whether there are abnormalities in the number or structure of chromosomes. If you're curious about chromosome structure and what kinds of abnormalities can occur, that's what chromosome basics covers.

Frequently Asked Questions

Can you only get a paternity test done at a hospital?

A paternity test intended to carry legal weight needs to go through an accredited institution, following a defined procedure and identity verification β€” a privately arranged test done outside that process may not be recognized as legally valid.

If a DTC genetic test shows a high disease risk, should I go straight to the hospital?

A DTC test result is statistical reference information, not a confirmed diagnosis, so rather than jumping to a conclusion if the result worries you, it's better to consult a specialist about whether any further, more precise testing is actually needed.