Approximately 42 years ago, the Berg acid phosphatase (AP) test(1)was accepted in most rape treatment centers nationally as the standard to determine whether sexual intercourse or related actions in any form had occurred. More specifically, the test was designed to determine the presence of a certain enzyme. In October 1969, I published an article making the test simpler(2)and reviewing the history of various tests for the detection of AP, an enzyme found in great abundance in seminal fluid. Both AP-impregnated material and refrigerated reagents had been saved along with a quantity of seminal fluid used in the original tests. The objectives of this study were to determine whether 25-year-old seminal fluid in any form can still be identified by the AP test and whether 25-year-old chemicals have remained stable and are still usable.