Frequently asked questions

Questions and answers

What is the Strip Detective test?

Strip Detective is a test analogous to those used in forensic investigations. Its purpose is to detect acid phosphatase, which is specific to semen. A positive test result confirms the presence of acid phosphatase in the tested material as preliminary evidence of the presence of sperm in the tested material. 

A positive test, like any home test, must be confirmed by a test performed in a certified laboratory to be completely sure of the result.

It should be noted that in rare cases, acid phosphatase is also present in bacteria and other substances of biological origin, which is why a positive test requires confirmation.

The manufacturer is not responsible for how the test is performed.

The test will detect even several-year-old semen stains.

A positive result for acid phosphatase will cause the test field to turn purple. Compare the color of the test with the reference range on the box and check the result.
Below are some sample photos of positive results.

A negative test result will not change the color of the test field to purple. It may be slightly yellow or slightly pink. Compare the color of the test with the reference range on the box and check the result.
Below are some sample photos of negative results.

If you have doubts about the test result, you can perform a negative control using an unused swab.

How to perform a negative control? Rinse the unused stick with running water or bottled water. Wait 2 minutes. Compare the color of the stick with your result. If the shade of both sticks is similar, the test result is also negative.

If you check the test after 2 minutes and it is negative, and then later—for example, after 3 or 5 minutes—it changes to positive, you should interpret it as NEGATIVE!

If you are unsure about the final result, you can perform a negative control.

Take a fresh, unused strip out of the box and spray it with water. Wait 2 minutes and compare the result of the strip sprayed with water with your result. If the color of the result on the new strip is the same as yours, interpret your test as negative as well.

A more intense color indicates a higher concentration of acid phosphatase in the stain. The concentration of semen in the stain may vary depending on the amount of water used in the test, damage to the stain during washing, the effect of time, and other factors.

If the semen stain is not very diluted, the test will show a strong purple color.

The test can be used for one year from the date of manufacture. The expiration date is printed on the box.

We offer two testing methods – method A and method B, as described in the instructions. Use method B if you want to be sure that there will be no purple marks on fabrics and other materials – this method requires the additional use of a cotton swab (such as an ear cleaning swab) and will ensure that the tested material is not stained.

If you use method A, you may stain the material if the test is positive.

Use cold or cooled water (to room temperature) to perform the test. The water should be boiled to ensure its purity, but it should not be hot.

If the test field turns several colors, determine whether it also contains purple, matching the color indicated on the comparative color scale. If it also has purple, consider it positive. However, remember that acid phosphatase present in semen may also occur in rare cases in other biological substances, including bacteria, so you should confirm the result in a certified laboratory.

The result confirms that acid phosphatase is present in the trace. This result means that it could be semen, but it does not provide 100% certainty. In rare cases, acid phosphatase may also be present in bacteria (including bacteria from the female vagina) and in other biological substances or deodorants. For this reason, a positive result must be confirmed by a certified laboratory.

Performing the Strip Detective test does not destroy the DNA material. You can send your material to a certified genetic laboratory for further analysis. You can confirm the presence of semen, mark the DNA profile, or order a DNA profile and compare it with another profile.
The test will detect semen in both wet and dry traces. Wet traces must not be diluted with water or other liquids in a ratio of up to 1:500. We cannot guarantee the accuracy of the test for more diluted traces.
We do not guarantee the effectiveness of the test after 365 days from the date of manufacture. The expiration date of your kit is printed on the inside of the box.