Test Catalog

Test ID: I2SBS    
Iduronate-2-Sulfatase, Blood Spot

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

Whole blood is collected on a blood spot card. A 3-mm (one-eighth inch) disk is punched out of the dried blood spot (DBS) into a microcentrifuge tube and inactivated bovine serum albumin is added. The extraction liquid is combined a substrate in a black 96-well plate. A blank is prepared using only preincubation extraction liquid, substrate, and filter paper punch containing no blood. All patients, controls, and blanks are set up in duplicate. After two incubations, a stop buffer is added to all wells. Calibrators are prepared and analyzed on every plate to calculate enzyme activity results based on fluorescence units in patient wells versus calibrators. The calibration is derived from 4-methylumbelliferone that is serially diluted manually in the plate, with the highest calibrator being equivalent to an enzyme activity of 3.125 nmol/hour/mL. The plate is then ready to be read using the spectrofluorometer. Fluorescence readings for duplicate wells are averaged, and the average fluorescence is used to calculate the enzyme activity result.(Unpublished Mayo method)

PDF Report Indicates whether the report includes an additional document with charts, images or other enriched information


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


Report Available The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

8 to 15 days

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

1 year

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