Your saliva goes to a partner or in-house lab, where DNA is extracted, checked, prepared and sequenced. What happens to the leftover sample depends on the company and on the storage choice you make: some destroy it, some keep it in a biobank only if you agree, and some set a fixed retention period.
Destroying the sample is separate from deleting your digital results. If you want both gone, you must ask for both.
Before it ships: why the spitting rules matter
Most saliva kits tell you not to eat, drink, smoke or chew gum for a set time before collecting. One widely used kit family states 30 minutes, because those activities can lower the DNA concentration and yield. The tube usually contains a stabilising liquid that breaks open cells and preserves the DNA, which is why a sample can travel through the mail without refrigeration. The manufacturer of that kit says its collected samples stay stable at room temperature for up to 12 months.
Your kit may use a different product, so follow your own instructions. The principle is the same: a clean, correctly filled tube gives the lab enough DNA to work with. In an FDA review of one cleared saliva collection device, a study of 206 adults collecting at home found that 98.41% of samples contained enough DNA for testing.
The lab journey, step by step
For whole genome sequencing, the broad workflow described by sequencing-instrument makers has four stages.
- Receiving and logging. The lab matches the tube's barcode to your order and checks it for leaks, volume and damage. Samples that fail this check may be rejected before any chemistry starts.
- DNA extraction. The lab pulls DNA out of the saliva and measures how much it has and how clean it is. Low yield or contamination is the usual reason a kit needs a recollection.
- Library preparation. The DNA is broken into fragments and adapters are attached so the pieces can be read.
- Sequencing and analysis. Instruments read the fragments, software aligns them to a reference genome and calls variants, and the results become the files and report you receive. Our guide to FASTQ, BAM and VCF files explains those outputs.
If you are curious how deep the reading goes, see what 30x coverage means. Whether the lab is run by the company or a partner, and where it sits, can also matter for privacy and shipping, as we note in the international shipping guide.
Three things, not one: sample, extract and data
It helps to separate three items that people lump together.
- The leftover saliva tube. Whatever remains after the lab has taken what it needs.
- The extracted DNA. A purified aliquot that can be re-tested later without asking you for another sample.
- The digital data. Raw reads, variant files and reports stored on servers.
A company can destroy the first two and keep the third, or the reverse. Always ask which of the three a request covers.
What companies say about keeping samples
Policies vary and change after ownership changes, so read your provider's current pages. Two published examples show the range, as of October 2026.
| Provider | What its published policy says |
|---|---|
| Ancestry | Partner laboratories extract the DNA. You choose whether your sample is stored in its biobank for future testing. If you do not consent to storage, the sample is destroyed. You can ask for destruction through Member Services or by deleting your account. |
| 23andMe | Its biobanking consent describes an initial ten-year retention period. Customers who consented to research and made no biobanking choice may have samples kept longer, for research use only. Withdrawing biobanking consent in account settings leads to secure discard, and deleting the account destroys stored samples. |
Note that 23andMe's assets were sold in 2025 after its bankruptcy filing, so its current owner's terms matter. Our 23andMe timeline covers the sale. We did not verify the sample policies of other consumer sequencing companies for this article, so check theirs directly rather than assuming they match.
Choose at activation. Many companies ask for your storage preference when you register the kit. It is much easier to decline there than to chase a destruction request later. Keep a copy of every confirmation.
Do any laws force destruction?
Some places have rules. California's Genetic Information Privacy Act, in force since January 1, 2022, applies to direct-to-consumer genetic testing companies and lets a consumer ask for a stored biological sample to be destroyed, with the company having 30 days to comply. Other US states and the EU have their own genetic privacy rules with different scopes. We cover how those rights work for data in can you really delete your DNA data.
Clinical and legal-purpose labs follow different retention rules, often longer, so a test ordered by a doctor may not behave like a consumer kit.
What to ask your provider
- Is my leftover sample stored by default, or only if I consent?
- Is the extracted DNA kept as well as the saliva?
- For how long, and for what purposes (re-testing, research)?
- How do I request destruction, and will I receive written confirmation?
- Does destruction also delete my digital data, or is that a separate request?
- What happens to stored samples if the company is sold or closes?
These fit into the longer list in our questions to ask before buying whole genome sequencing.
Bottom line
Your saliva is processed in a few days of lab work, but your sample can outlive the report by years if you let it. Decide at activation whether you want it stored, keep written confirmation of your choice, and treat sample destruction and data deletion as two separate requests. For a wider look at how providers handle your information, read our privacy comparison.
Common questions
Do DNA testing companies keep my saliva after sequencing?
It depends on the company and on your choice. Some destroy the sample unless you consent to storage, and some set a fixed retention period. Read your provider's current policy and choose your storage preference when you activate the kit.
Is destroying my sample the same as deleting my data?
No. They are separate. Destroying the physical sample or extracted DNA does not necessarily delete the digital results, and deleting your account data does not always destroy a stored sample unless the policy says so. Ask for both if you want both.
Can a saliva sample be tested again later without a new kit?
If the company keeps your sample or extracted DNA, it could be re-tested or used in research where you consented. If it was destroyed, any new test would need a new sample.
Why do some saliva kits fail?
The usual reasons are too little DNA, contamination or an under-filled or damaged tube. Eating, drinking, smoking or chewing gum shortly before collecting can reduce DNA yield. Most providers offer a recollection if a sample fails.
Does the law force companies to destroy my sample?
Not everywhere. California's Genetic Information Privacy Act, in force since January 1, 2022, lets consumers ask direct-to-consumer genetic testing companies to destroy a stored sample within 30 days. Rules in other places differ.
Sources and verification
Verified October 2026 from the primary pages below. Provider policies change, especially after acquisitions, so confirm on the provider's current site. Other providers' sample policies were not verified.
- Ancestry Privacy Statement (biological samples; DNA data deletion)
- 23andMe, Update to Biobanking Consent (2024)
- TechCrunch, 23andMe bankruptcy and sale outcome (2025)
- Privacy Rights Clearinghouse, California Genetic Information Privacy Act
- DNA Genotek, Oragene Dx handbook (stabilising solution, room-temperature stability, pre-collection wait)
- FDA 510(k) review K192920, saliva collection device (home collection study)
- Illumina, whole genome sequencing workflow overview
Medical disclaimer. GenomeTesting.org publishes educational content about genetics and consumer genomic testing. Nothing here is medical advice, a diagnosis, or a substitute for care from a qualified clinician or genetic counsellor. Decisions about testing, treatment, or interpreting your own results should be made with a healthcare professional who can see your full history.