When the father can't be tested -- whether he's deceased, missing, or refusing to participate -- a grandparent DNA test is the most practical alternative. But once you've decided to go that route, the next question is which provider to use. There are real differences between grandparent DNA test kits in terms of price, marker count, turnaround time, and accreditation. Those differences matter more for grandparent testing than for a standard paternity test.
This article compares four grandparent DNA test providers side by side -- what to look for, how each option stacks up, and why some technical details like marker count carry more weight for this particular type of test.
If you're looking for a general explanation of how grandparent DNA testing works, we have a separate guide that covers the science, accuracy, and process in detail.
Why Grandparent Testing When the Father Isn't Available
A direct paternity test is always the simplest answer when the alleged father is alive and willing. But life doesn't always cooperate. The father may have passed away, he may be unreachable, or he may refuse. In those cases, testing his parents -- the child's alleged grandparents -- is the most common workaround. If you're dealing with a posthumous paternity situation, grandparent testing is often the first recommendation.
The biology behind it is straightforward. A child inherits roughly 50% of their DNA from their father, and the father inherited 100% of his DNA from his two parents. So the child's paternal DNA came from the grandparents. By comparing the child's DNA to the grandparents' DNA, a lab can calculate whether the biological relationship exists.
The challenge is that grandparent-grandchild pairs share about 25% of their DNA on average, compared to the roughly 50% shared between a parent and child. That means the statistical analysis has less to work with. And that's exactly why your choice of provider and test specifications matters more for grandparent testing than it does for a standard paternity test.
Why Marker Count Matters More for Grandparent Tests
Most DNA relationship tests use Short Tandem Repeat (STR) analysis. The lab examines specific locations on the DNA -- called genetic markers -- where short sequences repeat in patterns unique to each person. The more markers a lab analyzes, the more data points it has to calculate the probability of a biological relationship.
For a standard paternity test, 20 markers is usually more than enough. Parent-child relationships share so much DNA that the math reaches 99%+ probability quickly. But grandparent testing is different. Since grandparent and grandchild share only about 25% of their DNA, each additional marker gives the lab meaningful extra information. The difference between 20 markers and 28 markers can be the difference between a conclusive result and an inconclusive one -- especially when only one grandparent is available to test.
If you want to understand how DNA testing works at a technical level, that guide covers STR analysis and marker selection in detail. For picking a grandparent test, what matters is that more markers generally means more statistical confidence -- and that confidence gap is larger for grandparent tests than for direct paternity tests.
What to Compare When Choosing a Grandparent DNA Test
Not every grandparent DNA test is the same. Here are the factors worth looking at before you order.
Total Cost
Grandparent DNA tests range from about $139 to $500 depending on the provider. Some include everything in one price. Others charge separately for the collection kit, lab processing, or return shipping. Always check what's included before comparing sticker prices.
Genetic Markers Tested
As covered above, marker count matters more for grandparent testing. The industry standard is 20 or more markers. Some labs go higher. More markers means more data for the statistical analysis, which matters when the shared DNA between participants is lower.
One Grandparent or Both
Testing both grandparents produces stronger results than testing just one. Make sure the provider you choose supports both-grandparent testing and understand what the additional cost looks like.
Mother's Sample
Including the biological mother's DNA sample dramatically improves accuracy. Her profile lets the lab subtract her genetic contribution and isolate the markers the child inherited from the father's side. Check whether the provider offers this option and what it costs.
Legal vs. Peace of Mind
If you need results for court, immigration, custody, or estate proceedings, you'll need a legal test with chain-of-custody documentation. Not every provider offers legal grandparent testing. If your situation may end up in court, verify legal options upfront.
Turnaround Time
Lab processing time varies by provider. Some deliver results in 2-3 business days after receiving samples. Others take a week or more. Keep in mind that total time also depends on shipping -- how long it takes to get the kit to you and how long it takes your samples to reach the lab.
Grandparent DNA Tests Compared
Below is a closer look at four providers that offer grandparent DNA testing. Competitor pricing and specifications are approximate, pulled from publicly available information. Prices and policies change, so confirm directly with each provider before ordering.
US Diagnostics Center
The grandparent DNA test kit from US Diagnostics Center is priced at $139, which includes the collection kit, lab processing, and a prepaid return shipping envelope. The lab analyzes up to 28 genetic markers -- higher than the industry standard of 20 or more. Lab processing takes 2-3 business days after samples arrive.
USDC is BBB Accredited with an A- rating and is currently pursuing AABB accreditation. The mother's sample can be added during checkout to strengthen results, which is especially recommended for grandparent tests. Both-grandparent testing is supported.
The main tradeoff with USDC is the lack of AABB accreditation, which means the grandparent test is currently available as a peace-of-mind (informational) test only. If you need legally admissible results for court or immigration, you'll need an AABB-accredited provider. On the other hand, at $139 with up to 28 markers, USDC offers more data points per dollar than most competitors.
EasyDNA
EasyDNA is an international DNA testing company that has been in business for over a decade. Their grandparent test runs approximately $199-$299 depending on the options selected. They analyze 20 or more genetic markers, offer both peace-of-mind and legal grandparent testing, and report results in roughly 3-5 business days.
EasyDNA's main advantages are their international reach and competitive mid-range pricing. If you need legal testing, verify their current AABB accreditation status directly with the company before ordering, as accreditation requirements vary by jurisdiction.
PaternityUSA
PaternityUSA's grandparent DNA test falls in an approximate $200-$350 range. They're AABB accredited with legal testing options and have been around for a while.
Price-wise, they land in the mid-range among grandparent test providers. If AABB accreditation is a requirement for your situation, PaternityUSA is one of the stronger options to consider.
ChoiceDNA
Grandparent testing from ChoiceDNA runs approximately $150-$300, with the final price depending on the type of test and options you add. They have both informational and legal testing available.
ChoiceDNA's pricing is competitive, though the range is broad enough that your final cost depends on which test and options you actually pick. Double-check the current price and what's bundled before you order.
Side-by-Side Comparison
| Feature | US Diagnostics Center | EasyDNA | PaternityUSA | ChoiceDNA |
|---|---|---|---|---|
| Total Cost | $139 | ~$199-$299 | ~$200-$350 | ~$150-$300 |
| Genetic Markers | Up to 28 | 20 or more | 20 or more | 20 or more |
| Lab Turnaround | 2-3 business days | ~3-5 business days | Varies | Varies |
| AABB Accredited | No (pursuing) | Verify directly | Yes | No |
| BBB Accredited | Yes (A-) | Verify directly | Yes | No |
| Legal Option | Not yet available | Yes | Yes | Yes |
| Mother's Sample Support | Yes (add during checkout) | Yes | Yes | Yes |
| Both Grandparents Option | Yes | Yes | Yes | Yes |
Competitor pricing and details are approximate and based on publicly available information. Confirm directly with each provider before ordering.
One Grandparent or Both?
If you have the option, test both grandparents. The difference in result strength is significant.
Here's why. A child inherits half their DNA from their father, and the father inherited half from each of his parents. When you test only one grandparent, the lab can only see half of the paternal DNA picture. The child may have inherited markers from the other grandparent -- the one not being tested -- and those won't show up as matches. That can weaken the statistical probability, sometimes enough to produce an inconclusive result.
When both grandparents are tested together, the lab has the complete paternal DNA picture. Every marker the child inherited from the father's side should match one grandparent or the other. That gives the analysis much more to work with, and probability of relatedness above 99% becomes achievable in most cases.
If only one grandparent is available, adding the biological mother's DNA sample becomes even more important. The mother's profile lets the lab subtract her contribution, isolating only the markers that came from the father's side. That partially compensates for having only one grandparent in the test. If you're weighing your options between sibling testing or aunt/uncle testing as alternatives, those articles explain when each test type makes more sense.
When You Need a Legal Grandparent Test
A peace-of-mind grandparent test tells you the answer for your own knowledge. But some situations require results that hold up in court or satisfy a government agency. These include:
- Immigration cases -- proving a biological family relationship for visa or citizenship applications
- Custody or visitation -- grandparents establishing biological connection to support custody petitions
- Estate and inheritance disputes -- proving a grandchild is biologically related to the deceased
- Child support enforcement -- establishing paternity indirectly when the father is unavailable
Legal tests require chain-of-custody procedures: a neutral third-party collector verifies identities, witnesses sample collection, and seals the kit with documentation. The samples are tracked from collection through lab analysis to results. This chain of custody is what makes the results admissible.
For legal grandparent testing, AABB accreditation is typically required. If your case will end up in court or before a government agency, choose an AABB-accredited provider like PaternityUSA. For more on how legal testing works, see our article on the court-ordered paternity test process.
Frequently Asked Questions
Can a grandparent DNA test prove paternity if the father is deceased?
Yes. A grandparent DNA test can establish a biological link between the child and the father's family. Since the father inherited all of his DNA from his parents, testing the grandparents provides an indirect but scientifically valid way to determine paternity. Testing both grandparents plus the mother's sample produces the strongest results.
How accurate is a grandparent DNA test with only one grandparent?
Testing with one grandparent can still produce meaningful results, but the statistical probability may be lower than with both grandparents. Adding the biological mother's sample significantly improves accuracy when only one grandparent is tested, because it helps the lab isolate the paternal DNA markers. The number of genetic markers tested also makes a bigger difference in one-grandparent scenarios -- more markers mean more data to work with. For a deeper look at accuracy considerations, see our article on what the science says about accuracy.
What's the difference between a peace-of-mind and a legal grandparent test?
A peace-of-mind test gives you a personal answer. You collect samples at home and mail them in. A legal test adds chain-of-custody procedures -- a neutral collector verifies identities, witnesses the collection, and maintains documented control of the samples. Legal results can be submitted to courts and government agencies. Peace-of-mind results cannot.
Do I need the mother's DNA for a grandparent test?
It's not required, but it's strongly recommended. The mother's sample lets the lab subtract her genetic contribution and focus on the markers the child inherited from the father's side. This makes the analysis significantly more precise. At US Diagnostics Center, you can add the mother's sample during checkout.
Why is USDC's grandparent test less expensive than competitors?
USDC operates as a direct-to-consumer testing service without a network of physical collection sites. That lowers overhead. The $139 price includes the collection kit, lab processing with up to 28 genetic markers, and a prepaid return shipping envelope. No hidden fees or separate charges.
Can I use a grandparent test for immigration purposes?
Immigration DNA testing typically requires AABB-accredited lab work and specific chain-of-custody procedures. USDC is currently pursuing AABB accreditation and does not yet offer immigration testing. For immigration cases, choose a provider that is AABB accredited and confirms they support immigration-specific requirements.
Related Reading
- Grandparent DNA Test: How It Works, What It Costs, and When You Need One
- Paternity Testing After Death: Is Posthumous DNA Testing Possible?
- Sibling DNA Test Kit: How It Works and When You Need One
- Aunt and Uncle DNA Test: How Avuncular Testing Works
- How DNA Testing Works: A Complete Step-by-Step Guide
- Court-Ordered Paternity Test: Process, Cost, Timeline
Part of our guide: Kinship DNA Testing: Sibling, Grandparent, and Family Relationship Tests
0 comments