Forensic Testing – Infidelity Testing

Infidelity testing is the process of testing garments and other materials for the presence of semen or other biological fluids that if positive can support a claim that a partner has been unfaithful. Because the DNA Reference Laboratory is ASCLD-LAB International accredited, our infidelity testing can either be performed for legal purposes requiring all relevant chain of custody information, or for piece of mind, where there is minimal chain of custody required.

Our infidelity testing process involves four steps.

The first step, screening, is performed on the item(s) using a highly sensitive blue light source capable of revealing hidden stains such as semen.

The second step, presumptive testing, begins on the stains in question. Using chemical indicators, a small sample of the stain is screened to determine if the stain could contain a particular biological fluid.

The third step, confirmatory testing, involves more powerful chemical indicators or microscopic testing and allows a small sample of the stain to be thoroughly examined for the presence of that particular biological fluid or the presence of sperm in the case of semen screening. This test will also allow us to detect the presence of a bacterial or yeast infection that can mask itself as a potential semen stain.

The fourth step is DNA analysis. If positive for semen, blood, saliva, etc., the client may submit a sample of his/her own DNA for comparisons against the questioned stain to rule out the possibility of the stain belonging to him/her. Any personal effects or items containing DNA from individuals in question may be submitted for comparison to the questioned stain, but understand that even in a legal case, a court ordered reference sample is required from an individual in order to legally bind him/her to the evidence if we can not exclude.

When submitting a non-legal sample:


  • Please collect the sample using gloves, place in a paper bag or envelope, seal the container, and bring the item into the lab

When submitting a legal sample:


  • Photograph the evidence before handling the item. Place a ruler or a coin next to the item before photographing so there is a frame for size referencing.
  • Use gloves to pick up the item. Otherwise your DNA can easily be transferred to the item.
  • Package the item in a paper bag or envelope. Plastic bags induce mold, especially in the heat.
  • Seal the bag or envelope with packaging tape, signing across the tape with your initials and the date.
  • Note the time, date and location where the collection was made.
  • Bring the sample to the lab and fill out our chain of custody forms for legal delivery.