Imperial Collage Healthcare

ALP Isoenzymes

Test Background
The alkaline phosphatases are zinc metalloproteases expressed in most tissues of the body, at particularly high concentrations in intestinal epithelium, kidney tubules, bone (osteoblasts), liver & placenta. Their precise function in vivo is not known, but it is associated with lipid transport in the intestine and calcification in bone. Measurement by isoelectric focusing electrophoresis can determine specific isoenzyme contributions. Serum ALP Isoenzyme measurements are of interest in determining the potential cause of an increased Total ALP result.

Clinical Indications
Pathological causes are primarily associated with hepatobiliary and bone (associated with increased osteoblast activity) disorders. Other causes of increased isoenzyme fractions may include physiological bone growth, benign transient hyperphosphatasaemia (BTH), malignant disease, pregnancy, diabetes and CRF.

Reference Range

Sample Required
Serum (samples containing EDTA, Citrate or Oxlate are NOT suitable)

Sample Volume
100 µl


Stable at 2-8oC for 72 hours. Please freeze pending dispatch for analysis.

Sample can be sent by first class post.

Turnaround Time
2 week


Please include Total ALP and gGT results on request form if available.

Specimens containing inhibitors of alkaline phosphatase activity e.g. heparin, EDTA, citrate, fluoride or iodoacetate are unsuitable.

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