Alpha-Galactosidase, Blood Spot
Method Description Describes how the test is performed and provides a method-specific reference
Whole blood is collected on grade 903 (Whatman) filter paper. A one-eighth inch (3-mm) disk is punched out of the dried blood spot into a 96-well plate. 20 mcL of 0.25 M N-acetyl-D-galactosamine is added as elution liquid/inhibitor and 50 mcL of 5 mM 4-methylumbelliferyl-alpha-D-galactopyranoside in 0.15 M cit-phos buffer as the substrate (70 mcL total volume plus dried blood spot). After the incubation period (20 hours at 37 degrees C), all of the liquid from the plate is manually transferred to a second 96-well plate. 200 mcL of stop buffer (150 mM EDTA, pH 11.4) is added to all wells. A calibration is added to every plate and is derived from 4-methylumbelliferone (4-MU) that is serially diluted manually in the plate with the highest calibrator being equivalent to an enzyme activity of 12.2 nmol/mL/hr. The plate is then read on the spectrofluorometer. Fluorescence readings for duplicate wells are averaged and the average fluorescence is used to calculate the enzyme activity result.(Poeppl AG, Murray GJ, Medin JA: Enhanced filter paper enzyme assay for high-throughput population screening for Fabry disease. Anal Biochem 2005;337:161-163)
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.
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.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test