The evaluation of a new enzyme immunoassay for the measurement of prostatic acid phosphatase

An enzyme immunoassay for prostatic acid phosphatase (PAP) has been assessed. An upper limit of normal is set at 1.8 μg/1. There is a very low incidence of raised levels in chronic disease or cancers other than those of the prostate. Patients with well-controlled prostatic cancer have levels < 1.8 μg/1 and show little variation about their own mean. PAP can rise exponentially with a doubling time of 1–5 months. This assay is unlikely to increase the detection of asymptomatic prostatic cancer as 66% of T 0–2N xM 0 cases had PAP < 1.8 μg/l. The main advantages over routine enzyme assays are its sensitivity and accuracy in the lower range.