Types of genetic tests
MedlinePlus groups genetic tests by what they look at:
- Molecular (DNA) tests read the DNA sequence. They range from a single known variant (often used for relatives of someone who carries it), to one whole gene, to a gene panel of several genes, to whole exome or whole genome sequencing, usually when narrower tests haven't found a cause.
- Chromosomal tests look for large changes, such as an extra or missing chromosome or a missing or duplicated segment.
- Gene expression tests measure which genes are switched on or off in cells, often used in cancer.
- Biochemical tests measure the amount or activity of proteins or enzymes that genes make.
What genetic testing is used for
- Diagnostic testing confirms or rules out a genetic condition when symptoms suggest one.
- Carrier testing shows whether you carry one copy of a variant that causes disease only with two copies, often before or during pregnancy.
- Prenatal and newborn screening look for conditions before or just after birth.
- Predictive testing looks for variants linked to conditions that appear later in life, such as inherited cancer risk, in people without symptoms.
- Pharmacogenetic testing shows how your genes may affect your response to certain medicines, such as some antidepressants, statins and warfarin. It can't diagnose a condition.
- Tumor testing looks at changes in cancer cells to guide treatment; see biomarker testing.
Clinical genetic tests vs consumer DNA kits
| Clinical test | Consumer (direct-to-consumer) kit | |
|---|---|---|
| Who orders it | A clinician or genetic counselor | You, online or in a store |
| Sample | Blood, saliva or cheek swab | Spit or cheek swab mailed to the company |
| Use | Can diagnose and guide treatment | Traits, ancestry, wellness and some risk reports; not for diagnosis on its own |
| Insurance | Often covered in part or full when medically necessary | Generally not covered; sometimes HSA or FSA eligible |
The FDA reviews some consumer genetic health risk tests but generally not wellness or ancestry tests. It notes that a consumer kit may not check every relevant variant, a negative result doesn't rule out risk, and different companies can read the same DNA differently. Don't change your health care based on a consumer result without talking to a clinician.
How to get genetic testing
- Start with why. A personal or family history of cancer, heart disease at a young age, or a known family variant are common reasons. Tell your primary care clinician.
- Ask about genetic counseling. A genetic counselor can help choose the right test and explain what results could mean for you and your family.
- Check coverage first. Ask your insurer whether the test is covered and whether it needs prior authorization. See does insurance cover genetic testing and genetic testing cost.
- Know your protections. The federal GINA law bars health insurers and employers with 15 or more workers from using genetic information against you. It doesn't cover life, disability or long-term care insurance.
Already have results from a consumer kit or a past panel? Gabriel can explain any lab report free in plain words.
Common questions
What is the difference between genetic testing and a DNA test?
"DNA test" usually means a consumer kit for ancestry, traits or wellness. Clinical genetic testing is ordered by a clinician to diagnose a condition or guide care, and its results can be used for medical decisions.
What doctor orders genetic testing?
A clinician orders clinical genetic tests: your primary care clinician or a specialist, often working with a genetic counselor who helps choose the test and explain results.
How long do genetic test results take?
MedlinePlus says a few days to several weeks after the sample is collected. Prenatal results usually come back faster.
Are consumer DNA tests accurate enough for health decisions?
Not on their own. MedlinePlus and the FDA say a consumer result usually needs a clinical test before it is used to diagnose a condition or make treatment decisions.
Can my genetic test results be used against me?
GINA bars health insurers and most employers from using genetic information in coverage and job decisions. It doesn't protect against use by life, disability or long-term care insurers.
Sources
- What are the types of genetic tests? MedlinePlus Genetics, U.S. National Library of Medicine
- What are the different ways genetic testing is used? MedlinePlus Genetics, U.S. National Library of Medicine
- What is direct-to-consumer genetic testing? MedlinePlus Genetics, U.S. National Library of Medicine
- Direct-to-Consumer Tests U.S. Food and Drug Administration
- Pharmacogenetic Tests MedlinePlus, U.S. National Library of Medicine
- Can genetic information be used against me? MedlinePlus Genetics, U.S. National Library of Medicine
This guide is general information, not medical advice. It does not replace a visit with a licensed clinician. Gabriel membership is not health insurance.