Prostatic Acid Phosphatase (PAP)

CPT: 84066
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  • Acid Phosphatase, Prostatic

Special Instructions

This test is not the same as Acid Phosphatase.

Values obtained with different assays should not be used interchangeably in serial testing. It is recommended that only one assay method be used consistently to monitor each patient's course of therapy. This procedure does not provide serial monitoring; it is intended for one-time use only. If serial monitoring is required, please use the serial monitoring number 480152.

Expected Turnaround Time

2 - 3 days

Related Documents

Specimen Requirements


Serum, frozen


0.5 mL

Minimum Volume

0.2 mL (Note: This volume does not allow for repeat testing.)


Red-top tube or gel-barrier tube; do not use acid phosphatase transport tube.


Transfer the serum into a Labcorp PP transpak frozen purple tube with screw cap (Labcorp No.49482). Freeze immediately and maintain frozen until tested. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.

Storage Instructions


Causes for Rejection

Plasma specimen; specimen not frozen

Test Details


An adjunct in the evaluation of possible prostatic malignancy and useful in monitoring therapeutic progress


Immunochemiluminometric assay (ICMA)

Reference Interval

0−3.5 ng/mL

Additional Information

Prostatic acid phosphatase has been used as a tumor marker ever since the observation by Gutman in 19381 that elevated levels of this enzyme are found in patients with metastatic prostate cancer. PAP determination in conjunction with PSA measurements is useful in assessing the prognosis of prostate cancer.2 Measurement of two markers allows identification of prostate cancer patients who have an elevation of PAP but not of PSA, and thus help monitoring the course of disease and response to treatment. PAP is more specific than PSA and less false-positives are seen due to benign prostatic hyperplasia.


1. Gutman AB, Gutman EB. An “acid” phosphatase occurring in the serum of patients with metastasizing carcinoma of the prostate gland. J Clin Invest. 1938 Jul; 17(4):473-478. 16694594
2. Powell P, Neal D, Gibb I, Wilson L, Hall R. Immunologically measured serum markers and their role in the management of prostate cancer. Eur Urol. 1988; 15(1-2):48-53. 2463921


Killian CS, Emrich LJ, Vargas FP, et al. Relative reliability of five serially measured markers for prognosis of progression in prostate cancer. J Natl Cancer Inst. 1986 Feb, 76(2):179-185.2418245


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
004747 Prostatic Acid Phos, Serum 20420-6 004748 Prostatic Acid Phos, Serum ng/mL 20420-6

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