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Test ID: ALKI
Alkaline Phosphatase, Total and Isoenzymes, Serum

Method Description Describes how the test is performed and provides a method-specific reference

Total Alkaline Phosphatase (ALP):

ALP cleaves p-nitrophenyl phosphate in the presence of magnesium ion to yield phosphate and p-nitrophenol. The rate of p-nitrophenol formation is directly proportional to the ALP activity and is determined photometrically at 450 nm. (Package insert: Roche Alkaline Phosphatase reagent; Indianapolis, IN, March 1999)

 

ALP Isoenzymes:

Serum samples are electrophoresed through alkaline buffered (pH 9.1) agarose gels. Almost all ALP isoenzymes can be separated by electrophoresis according to their charge difference. However, because the electrophoretic mobilities of the liver and bone isoenzymes are quite similar, a modification is required for separation. The Sebia system utilizes differences between liver and bone isoenzyme sialation in order to achieve separation. Each sample is applied to the agarose gel in duplicate. One sample is passed through wheat germ lectin (wheat germ agglutin [WGA]) and is deposited anodally from the point of sample application. The bone isoenzyme, which is rich in sialic acids, reacts with WGA and precipitates adjacent to the lectin application point. The separated isoenzymes are visualized using a specific chromogenic substrate, 5-bromo-4-chloro-3-indolyl phosphate/nitro blue tetrazolium in aminomethyl propanol (AMP) buffer, pH 10.0. The dried gels are read on a densitometer for the quantification of tissue isoforms. (Package insert: Sebia Hydragel 7 & 15 ISO-PAL, Sebia, Norcross, GA)

Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.

Alkaline Phosphatase: Monday through Sunday; Continuously

Alkaline Phosphatase Isoenzymes: Monday through Friday

Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.

2 days

Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result

4 days

Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

See Individual Unit Codes

Performing Laboratory Location The location of the laboratory that performs the test

Rochester