How to Collect DNA Samples for Infidelity Testing
If you're considering infidelity DNA testing, one of the most important steps is properly collecting and preserving the item you want tested.
Clothing, bedsheets, underwear, condoms, tissues, and other personal items may contain biological material that can be analyzed for semen, saliva, or human DNA.
However, improper collection, handling, or storage can damage biological material, introduce additional DNA, or reduce the chances of obtaining useful results.
At Validity Genetics, we offer specialized infidelity DNA testing services that can detect certain bodily fluids, recover DNA from personal items, and compare DNA profiles with known individuals.
This guide explains how to collect DNA samples for infidelity testing, how to package and ship them, and what to avoid before submitting an item for laboratory analysis.
What Samples Can Be Used for Infidelity DNA Testing?
Infidelity DNA testing generally involves examining a personal item or biological stain rather than collecting a standard cheek swab from the item itself.
These are commonly referred to as non-standard samples, or NSS.
Examples of items that may be suitable for testing include:
Underwear: May contain semen, vaginal secretions, saliva, or other biological material.
Bedsheets and pillowcases: May contain biological stains or transferred DNA.
Clothing: Shirts, pants, and other fabrics may contain bodily fluids or cellular material.
Condoms: May contain semen or other biological material, depending on their use and condition.
Tissues and wipes: May contain saliva, semen, or other biological material.
Towels and washcloths: May contain biological stains, although washing and moisture can affect DNA recovery.
Swabs of biological stains: May be useful when the original item cannot be submitted.
Not every item will contain enough recoverable DNA for testing.
The type of biological material, how the item was handled, environmental conditions, and the amount of time since the material was deposited can all affect the outcome.
Whenever possible, contact the laboratory before attempting to collect or transfer a biological stain. Submitting the original item is often preferable to collecting the stain yourself.
Step 1: Handle the Sample as Little as Possible
The first rule of collecting DNA samples for infidelity testing is simple:
Avoid unnecessary handling of the item or stained area.
Human DNA can be transferred through skin contact, saliva, sweat, and other biological material.
Touching an item repeatedly may introduce additional DNA, potentially complicating the analysis.
When handling a sample:
Wear clean, disposable gloves whenever possible.
Change gloves between different samples.
Avoid touching visible stains or areas likely to contain biological material.
Handle clothing or fabric by areas away from the suspected stain.
Keep samples away from other people's personal items.
Do not allow different samples to touch one another.
If you have already handled an item without gloves, this does not automatically mean it cannot be tested.
However, let the laboratory know if the item may have been handled by multiple individuals.
This information can be helpful when interpreting possible DNA mixtures.
Step 2: Allow Wet Samples to Air-Dry
Moisture is one of the biggest concerns when preserving biological samples.
Wet biological material can support microbial growth and accelerate DNA degradation.
If a fabric or swab is damp, it should generally be allowed to air-dry completely before packaging.
How to Dry a Biological Sample
Place the item in a clean, protected location where it will not come into contact with other objects.
Allow it to dry naturally at room temperature.
Keep it away from direct sunlight, excessive heat, and humidity.
Avoid touching or disturbing the suspected biological stain.
Once completely dry, package the item in clean paper packaging.
Do not use a hair dryer, heater, microwave, or other heat source to speed up drying.
Heat and moisture can damage biological material and reduce the likelihood of successful testing.
What About Liquid Samples?
Liquid biological samples require different handling from dried stains.
If you have a sample containing liquid semen, saliva, or another bodily fluid, contact Validity Genetics before attempting to transfer or package it.
Do not place wet biological material into a sealed paper envelope or attempt to dry a liquid sample using heat.
The appropriate collection and shipping method depends on the sample and the testing requested.
Step 3: Collect Dried Stains Carefully
Dried stains on clothing, bedding, or other surfaces are among the most common samples submitted for infidelity DNA testing.
These stains may contain biological material that remains suitable for testing even after drying.
Collecting Dried Stains on Clothing or Fabric
Whenever possible, submit the entire item containing the suspected stain.
For example, if you suspect semen or saliva on a pair of underwear, sending the complete garment allows the laboratory to examine the relevant area and select an appropriate sampling method.
If the item is too large to mail, such as a bedsheet or blanket, you may be able to submit a section containing the stain.
When cutting a stained fabric sample:
Use clean cutting tools and avoid touching the stain.
Cut around the suspected stained area, leaving approximately one to two inches of surrounding material when practical.
Avoid cutting directly through the stain.
Place the fabric section into a clean paper envelope.
Label the envelope with the sample description and collection information.
Be aware that cutting a stain from an item may permanently damage it.
Laboratory testing may also consume or alter some of the submitted material.
Collecting Dried Stains From Hard Surfaces
If a stain is located on a surface that cannot be submitted, such as furniture or another fixed object, a swab collection may be necessary.
However, collecting a dried stain with a wet swab can dilute the material, transfer unwanted DNA, or make later laboratory analysis more difficult.
We recommend contacting Validity Genetics before swabbing a dried stain yourself.
If swabbing is appropriate, we can provide instructions based on the type of surface, suspected biological material, and testing needed.
In some situations, submitting the original item or a removable portion of it may provide a better opportunity for analysis.
Step 4: Package Each DNA Sample Separately
Proper packaging helps protect samples from moisture, contamination, and accidental mixing during shipping.
For most dry non-standard biological samples, we recommend clean paper envelopes or paper bags rather than plastic bags.
Paper packaging allows residual moisture to escape and reduces the risk of trapping humidity around biological material.
How to Package Samples
Make sure the sample is completely dry.
Place each item in its own clean paper envelope or bag.
Avoid folding or pressing directly against visible biological stains when practical.
Seal the envelope securely.
Do not combine multiple samples in the same envelope.
Keep oral reference swabs separate from non-standard samples.
If submitting multiple items, each should be individually packaged and clearly labeled.
Why Shouldn't You Use Plastic Bags?
Plastic can trap moisture, particularly when a sample has not dried completely.
This can create conditions that promote biological degradation.
For this reason, breathable paper packaging is generally preferred for dried biological samples.
If an item is already sealed in plastic, contact us before opening or repackaging it, particularly if it contains liquid material or could leak.
Step 5: Label Every Sample Clearly
Correct labeling helps the laboratory identify each submitted item and understand what testing has been requested.
Each sample envelope should include:
Test Order Number: Your Validity Genetics order number.
Sample Description: For example, underwear, bedsheet stain, tissue, or toothbrush.
Collection Date: The date the item was collected or packaged.
Estimated Sample Age: When the suspected stain may have occurred, if known.
You do not need to know exactly when a stain was deposited.
An approximate date or description is sufficient when the information is available.
For example:
Test Order #: 12345
Sample: Blue underwear, suspected stain
Collection Date: October 15, 2026
Estimated Sample Age: Approximately one week
If submitting multiple items, label them Sample A, Sample B, and so on, using the same identifiers on your paperwork.
This helps prevent confusion when different tests are requested for different items.
Step 6: Store DNA Samples Properly Before Shipping
If you're not ready to ship the samples immediately, proper storage can help preserve the biological material.
For most dried samples:
Store them in a cool, dry location.
Keep them away from direct sunlight.
Avoid excessive heat and humidity.
Keep each sample separately packaged.
Avoid unnecessary handling or repeated opening of the envelopes.
Do not store damp biological material in a sealed plastic container.
How Long Do DNA Samples Last?
DNA can remain recoverable from dried biological material for extended periods under favorable conditions.
However, there is no guaranteed period during which every sample will remain suitable for testing.
The age of the stain, the original amount of biological material, exposure to moisture, washing, sunlight, and other environmental conditions all affect DNA preservation.
Even older samples may sometimes yield useful DNA, while relatively recent samples can fail if they contain very little biological material or have been improperly stored.
Step 7: Choose the Right Infidelity DNA Test
Before sending your samples, it's important to understand what you want the laboratory to determine.
Different infidelity DNA tests answer different questions.
Semen Detection Testing
A Semen Detection Test examines a submitted item for the presence of human seminal fluid.
At Validity Genetics, we use a confirmatory RSID semen test that detects semenogelin, a protein associated with human semen.
This test can help determine whether semen is present on clothing, bedding, or another submitted item.
Semen detection does not identify who deposited the material or establish when it was deposited.
Simple Infidelity DNA Testing
Our Simple Infidelity DNA Test attempts to recover and analyze human DNA from a submitted item.
The results may indicate whether male DNA, female DNA, or a mixture of DNA profiles was detected.
This test does not include a comparison against a known individual's DNA.
Advanced Infidelity DNA Testing
Our Advanced Infidelity DNA Test includes DNA extraction and comparison with a known reference sample.
For example, if you submit an item containing an unknown DNA profile, the laboratory may be able to compare that profile with a cheek swab from a known individual.
The ability to perform a meaningful comparison depends on the quality and composition of the recovered DNA.
Complete Infidelity DNA Testing
Our Complete Infidelity DNA Test combines semen detection with DNA extraction and comparison.
This option may be appropriate when you want to determine whether semen is present and evaluate DNA recovered from the submitted item.
Y-STR Infidelity DNA Testing
In certain situations, male-specific Y-STR DNA testing may be useful, particularly when male DNA is present at low levels alongside a larger amount of female DNA.
Y-STR analysis examines markers on the Y chromosome and can help detect male genetic material in certain mixed samples.
However, Y-STR profiles are shared among males in the same direct paternal lineage, so they do not always uniquely identify an individual.
Learn more about Advanced Y-STR Infidelity DNA Testing.
Step 8: Ship Your DNA Samples to Validity Genetics
Once your samples are dry, individually packaged, and labeled, place them together with any required paperwork inside a larger shipping envelope or box.
We recommend using a shipping service that provides tracking, such as USPS, UPS, or FedEx.
Ship your samples to:
Genetics Services
500 S Main St
Las Cruces, NM 88001
Before shipping:
Confirm that each sample is properly labeled.
Include your order number and required documentation.
Make sure samples are securely packaged.
Keep a copy of your tracking number.
Follow any additional instructions provided with your order.
If you are unsure whether a particular item can be mailed safely or requires special packaging, contact us before shipping.
Common Mistakes to Avoid When Collecting Infidelity DNA Samples
Several common mistakes can reduce the chances of successful DNA testing.
Washing the Item Before Testing
Washing clothing or bedding can remove biological material and reduce the amount of recoverable DNA.
However, washed items may still contain detectable biological traces in some circumstances.
If an item has already been washed, let us know before ordering so we can help explain the available options.
Touching the Suspected Stain
Directly handling a stained area can introduce additional DNA or transfer biological material.
Handle items by unaffected areas whenever possible.
Packaging Damp Samples
Sealing damp biological material can encourage microbial growth and DNA degradation.
Allow appropriate samples to air-dry before packaging.
Combining Multiple Samples
Placing several items together can transfer biological material between them.
Package each item separately.
Attempting to Clean or Treat a Stain
Do not apply bleach, detergents, disinfectants, stain removers, or other chemicals to an item you intend to test.
These products can damage biological material or interfere with laboratory analysis.
Assuming a Visible Stain Contains DNA
Not every visible stain contains semen, saliva, or another biological material suitable for testing.
Similarly, biological material may be present even when a stain is not visible.
Laboratory testing is needed to determine what can actually be detected.
Can Infidelity DNA Testing Prove Someone Was Unfaithful?
Infidelity DNA testing can provide information about biological material found on a submitted item.
Depending on the test, the laboratory may be able to detect semen, recover DNA, or compare a DNA profile with a known individual.
However, DNA testing cannot establish the circumstances surrounding the biological material.
For example, testing cannot reliably determine:
When a biological stain was deposited
Whether sexual activity occurred
Whether a partner was unfaithful
How many sexual partners someone has had
Whether biological material was transferred directly or indirectly
Results should be interpreted within the limitations of the testing performed.
Frequently Asked Questions About Collecting Infidelity DNA Samples
Can I send underwear or bedsheets for semen detection?
Yes. Underwear, bedsheets, and other fabrics are commonly submitted for semen detection testing.
Whenever possible, send the complete dry item or an appropriate section containing the suspected stain.
Should I swab a stain or send the entire item?
We generally recommend submitting the original item whenever practical.
The laboratory can then examine the suspected area and select an appropriate collection method.
If the item cannot be submitted, contact us before attempting to swab the stain.
Can DNA be recovered from washed clothing?
Sometimes. Washing can remove or degrade biological material, but DNA or semen-related material may remain detectable under certain conditions.
Successful recovery cannot be guaranteed.
Can I collect multiple samples for infidelity DNA testing?
Yes. Multiple items can be submitted for testing.
Each sample should be packaged and labeled separately, and the testing order should account for the number of items submitted.
Do I need to send my own cheek swab?
Not necessarily.
Semen detection and simple DNA analysis can be performed without a known reference sample.
If you want the laboratory to compare recovered DNA with your DNA or another known individual's DNA, an appropriate reference sample will generally be needed.
Can I collect DNA samples without ordering a physical kit?
Yes. Validity Genetics offers an Electronic Instructions option for eligible infidelity DNA testing orders.
This allows customers to receive collection and shipping instructions electronically without having a physical kit mailed to their address.
How long does infidelity DNA testing take?
Standard infidelity DNA testing generally takes 5–7 business days after the laboratory receives and checks in the samples.
Business days are Monday through Friday, excluding weekends and holidays.
Rush testing may be available when arranged before laboratory processing begins.
Are infidelity DNA test results admissible in court?
Validity Genetics' standard infidelity DNA testing services are intended for informational purposes and are not court-admissible.
If testing is related to a legal matter, consult an attorney before collecting or submitting samples.
Get Help Collecting Your Infidelity DNA Samples
Proper sample collection is one of the most important steps in successful infidelity DNA testing.
Handling items carefully, allowing appropriate samples to dry, using paper packaging, and avoiding contamination can help preserve biological material for laboratory analysis.
At Validity Genetics, we offer semen detection, DNA extraction, DNA comparison, and specialized Y-STR testing for a variety of non-standard samples.
Whether you're submitting underwear, bedding, clothing, or another personal item, our team can help you understand the appropriate testing options before you send your sample.
Explore our Infidelity DNA Testing services or contact Validity Genetics with questions about collecting, packaging, or shipping your samples.
