The acid phosphatase (AP) test is a routine assay used to screen casework items for the

possible presence of semen. This colour test is carried out on filter paper which is retained

after testing.In adults and elderly persons, the normal findings for acid phosphatase are 0.13-

0.63 U/L (Roy, Brower, Hayden; 37°C) or 2.2-10.5 U/L (SI units). Normal findings in

children are 8.6-12.6 U/mL (30°C), while normal findings in newborns are 10.4-16.4 U/mL

(30°C).