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November 7, 1980

Prostatic Acid Phosphatase by Radioimmunoassay: Sensitivity Compared With Enzymatic Assay

Author Affiliations

From the Laboratory of Pathology, The Swedish Hospital Medical Center, Seattle. Dr Lindholm is a Clinical Fellow of the American Cancer Society.

JAMA. 1980;244(18):2071-2073. doi:10.1001/jama.1980.03310180037030

Prostatic acid phosphatase values in 98 patients with prostatic carcinoma were measured by a commercial radioimmunoassay (RIA) and oy enzymatic assay. Forty-three carcinomas were staged by rigorous pathological criteria. Patients (N=129) with benign prostatic hyperplasia were the control group. At 94% specificity, sensitivities of the RIA vs the enzymatic assay for clinically staged patients were as follows: stage A, 22% vs 6%; 3, 29% vs 10%; C, 52% vs 38%; and D, 87% vs 80%. However, none of the seven patients with pathological stage A and B disease had a positive test result, and we suggest that variability in staging criteria accounts for the discrepant sensitivity claims reported. Prostatic acid phosphatase RIA should not be used for screening but as an adjunct for staging known prostatic carcinoma.

(JAMA 244:2071-2073, 1980)