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Alkaline phosphatase isoenzymes

Alias: API

Discipline: Clinical Chemistry

Test information: Alkaline phosphatase isoenzymes are used in the investigation of high alkaline phosphatase (ALP) in order to determine the source; liver, biliary, bone, intestinal and/or placental. High ALP due to infection/inflammation (high CRP) should be ruled out prior to requesting isoenzymes. It is recommended to repeat ALP on a fasting sample to see if intestinal ALP is a cause of raised levels. Please note, requests are vetted by the Duty Biochemist using clinical details and routine Biochemistry that have been performed. Alkaline phosphatase isoenzymes are also indicated in children under the age of 5 years old when transient hyperphosphataseamia of infancy is suspected.

Specimen Type(s)
  • Blood;
Other Acceptable Specimen Type(s)
Specimen Container - Adult
  • Gold Top SST BD;
Specimen Container - Paediatric
  • Clear - Plain;
  • N/A;
Part of a test profile?
Volume (min) of sample to be sent to laboratory
Patient Preparation, Sample Handling and Transport
Fasting sample.
Maximum add on time
Units and Reference Ranges / Interpretation
Comment report, either by the RCH Biochemist when sending away the sample for isoenzymes is not indicated or by Newcastle when analysis has been performed.
UKAS number
UKAS accredited test?

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Last updated: 04-12-2023