Type of test:  Blood
 Normal findings
 Adult/elderly: 0.13-0.63 units/L (Roy, Brower, Hayden; 37° C)
 or 2.2-10.5 units/L (SI units)
 Child: 8.6-12.6 units/mL (30° C)
 Newborn: 10.4-16.4 units/mL (30° C)
 Test explanation and related physiology
 Elevated levels are seen in patients with prostatic cancer that has metastasized beyond the capsule to other parts of the body, especially bone. The degree of elevation indicates the extent of disease. This test is rarely performed for this indication; there are better tumor markers , including prostate-specific antigen .
Because acid phosphatase is also found at high concentrations in seminal fluid, this test can be performed on vaginal secretions to investigate alleged rape. This is now the primary use of PAP testing. Acid phosphatase is a lysosomal enzyme. Therefore lysosomal storage diseases (e.g., Gaucher disease and Niemann-Pick disease) are associated with elevated levels.
 Interfering factors
 • Alkaline and acid phosphatases are very similar enzymes that differ in the pH at which they are identified. Any condition associated with very high levels of alkaline phosphatase may falsely indicate high acid phosphatase levels.
 • Falsely high levels of acid phosphatase may occur in males after a digital examination or after instrumentation of the prostate (e.g., cystoscopy) because of prostatic stimulation.
*  Drugs that may cause increased levels of acid phosphatase include alglucerase, androgens (in females), and clofibrate.
*  Drugs that may cause decreased levels include alcohol, fluorides, heparin, oxalates, and phosphates.
 Procedure and patient care
 • See inside front cover for Routine Blood Testing.
 • Fasting: no
• Blood tube commonly used: red
• Avoid hemolysis. Red blood cells contain acid phosphatase.
 • Note on the laboratory slip if the patient has had a prostatic examination or instrumentation of the prostate within the past 24 hours.
• Do not leave the specimen at room temperature for 1 hour or longer because the enzyme is heat and pH sensitive, and its activity will decrease.
 Abnormal findings
 Increased levels
 - Prostatic carcinoma
- Benign prostatic hypertrophy
 - Prostatitis
- Multiple myeloma
- Paget disease
- Hyperparathyroidism
 Metastasis to the bone
- Sickle cell crisis
- Thrombocytosis
- Lysosomal disorders (e.g., Gaucher disease)
- Renal diseases
- Liver diseases (e.g., cirrhosis)
- Rape