Acid phosphatase: An enzyme that acts to release phosphate under acidic conditions and is produced in the liver, spleen, bone marrow, and prostate gland. Abnormally high serum levels of acid phosphatase may indicate infection, injury, or prostate cancer.
Purpose Of The Test:
To diagnose the prostatic carcinoma by advising the estimation of Total acid phosphatase and the prostatic component.
These two enzymes stage the prostatic carcinoma and monitor the effectiveness of treatment.
The test for acid phosphatase can be done on a vaginal swab in rape cases. Because the seminal fluid is rich in acid phosphatase.
It is done on the serum of the patient and performs the test within one hour.
How to get good serum: Take 3 to 5 ml of blood in the disposable syringe or in vacutainer. Keep the syringe for 15 to 30 minutes and then centrifuged for 2 to 4 minutes to get the clear serum.
EDTA plasma is better because it stabilizes the acid phosphatase.
A morning sample is preferred.
The sample is stable for 24 hours at 2 to 8 °C.
Try to do the test immediately.
If serum is acidified below pH of 6.5 that will stabilize the enzyme.
It has poor stability in whole blood.
ACP is unstable at room temperature >37 °C.
ACP is unstable if the pH is >7.0.
The serum is separated immediately and the test is performed within one hour.
EDTA plasma is preferred that stabilizes the AP.
Avoid prostatic massage in the last 48 hours.
Hemolysis falsely raised the value.
50% of activity lost if kept at room temperature.
Acid phosphatase enzymes are found in lysosomes of various tissue like Prostate, bone, kidney, RBC, platelets, semen, liver and spleen.
Acid phosphatase (AP) which is derived from the prostate has a pH optimum of the range of 5 to 6.
The greatest concentration of AP activity occurs in the liver, spleen, milk, platelets, bone marrow, red blood cells, and the prostate gland.
The prostate is the richest source. The majority of AP arises from the RBCs and prostatic tissue.
AP enzymes are unstable especially at a temperature above 37 °C and at a pH level of above 7.0.
As the prostatic component (PAP) is not raised in the early prostatic diseases so this is not a good screening enzyme.
Total acid phosphatase consists of a one-half prostatic component and the rest of the liver, disintegrating platelets, and RBCs.
Acid phosphatase is a lysosomal enzyme, so the prostatic enzyme is found in the lysosome of prostatic epithelium and is a glycoprotein.
Total AP is raised in Bone diseases.
Prostatic acid phosphatase needs to be differentiated from the non-prostatic sources like RBCs source.
Total AP = AP after tartarate inhibition = Prostatic AP.
Total acid phosphatase
2.5 to 3.7 ng /mL or 2.5 to 3.7 µg/L.
or less than 3.0 mg /L.
Prostatic acid phosphatase = <2.5 ng/mL (0 to 0.6 U/L).