M-404 This presumptive seminal fluid test turns purple in the presence of Acid Phosphatase, one of the components of seminal fluid. Lightly moisten the swab and dab the stain. Rub the swab against the paper test strips. A purple color presumptively indicates the presence of seminal fluid. However, because the test is presumptive, it should not be mistaken for a laboratory exam for the presence of spermatozoa. This test will only yield results when used on dried stains. Each bottle includes 25 individual strips.