Turnaround times
The quoted turnaround time is from sample receipt in the laboratory, to results authorisation in the Laboratory Information Management system. The times do not include transport of specimen to the laboratory or the administrative process to print and post/email reports. Service users must allow for transport and reporting time when ordering tests.
Clinical background:
Human alkaline phosphatase enzyme is part of a group of enzymes (phosphoric monoester hydrolases) that catalyse the hydrolysis and transfer of a phosphate group at alkaline pH. While routinely included in the liver profile, it is found in many human tissues, e.g. liver, bone, kidney, intestine and placenta and may be elevated in a variety of hepatic and non-hepatic conditions as well as in normal adolescent growth. These isoenzymes can be separated by electrophoresis due to their differences in charge and sialation pattern.
Specimen container paediatric:
Serum (SST or plain tube)
Specimen container adult:
Serum (SST or plain tube)
Minimum volume paediatric:
0.5 mL
Minimum volume adult:
0.5 mL
Special requirements:
Fasting sample required.
Sample stability:
Unseparate sample: 4 days
Separated sample: 7 days at 15-25C, 7 days at 2-8C, 2 months at -20C
Availability:
Available during full access hours
Assayed weekly
Site of analysis: RVI
Interpretation:
The liver isoenzyme is the most frequently elevated. A wide group of associated liver conditions can lead to increases in the liver isoenzyme, e.g. viral hepatitis, cirrhosis, drug induced liver disease. It is also increased in malignancies with hepatic metastases, in cancer of the lungs and digestive tract and in lymphoma.
Biliary isoenzyme (L2) (also called fast liver or macrohepatic) is associated with fragments of cell membranes derived from cells lining the biliary tract or from aggregation in bile or plasma of liver ALP with lipid or protein, e.g. PBC. Increases may occur in cholestasis and biliary diseases (e.g., cirrhosis, viral hepatitis) and in malignancies with liver metastases.
Bone isoenzyme is elevated as a consequence of increased osteoblastic activity. Increased values are present in growing children and in adults over 50 years. Increased levels are found in Paget’s, rickets, osteomalacia and bone cancer. Renal disorders can also result in increased bone isoenzyme levels.
Intestinal isoenzyme(s) is increased in a variety of diseases of the digestive tract. This isoenzyme may also be increased with diabetes, chronic renal failure and cirrhosis of the liver, and in subjects with blood group 0 or B.
Placental isoenzyme(s) is found in serum of pregnant women, late in first trimester of pregnancy. It may also occur in a small proportion of patients with cancer.
Immunoglobulin complex or macro-alkaline phosphatase is a fraction that is rarely found. It remains very close to the application point on both tracks.
Lipoprotein-alkaline phosphatase complex also remains very close to the application point on both tracks. It may be found in biliary obstructive diseases.
Isoenzymes with atypical migrations, such as Nago, Regan and Kasahara, are difficult to identify.
Reference ranges:
Non-numeric result. Interpretative provided on report.