ACID PHOSPHATASE - plasma or serum

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Specimen: 5 mL blood in lithium heparin or plain tube. Defer collection for 72 hours after rectal examination, urethral instrumentation, prostatic massage or FNAB, as high levels may result from these procedures.

Method: Immunoassay, spectrophotometry.

Reference Interval: Method dependent - consult pathologist.

Application: Test largely superseded by prostate specific antigen assay, which has greater sensitivity and specificity for the detection of invasive or metastatic adenocarcinoma of the prostate.

Interpretation: The test is relatively specific for the prostatic isoenzyme. High levels indicate tumour extension beyond the prostatic capsule or metastatic spread. A normal level does not exclude the diagnosis of prostatic malignancy. The preferred test is PROSTATE SPECIFIC ANTIGEN .

Reference: Seamonds B et al. Urology 1986; 28: 472-479.

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