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|81330:ARYLSULFATASE A, LEUKOCYTES|
|Methodology:||Colorimetric / Kinetic|
|Edit Date:||8/31/2010 1:52:10 PM|
|Released:||72 hours after setup at PeaceHealth Laboratories’ reference lab|
|Specimen Collection Details|
|Collection:||One 8.5 mL yellow top tube (ACD). NOTE: Draw specimen Monday through Thursday only and not the day before a holiday. Specimen must reach reference lab within 48 hours of collection.|
|Handling:||Refrigerate. Do not transfer blood to other containers.|
|Stability:||48 hours refrigerated. Unstable frozen.|
|Standard Volume:||7 mL whole blood|
|Minimum Volume:||6 mL whole blood|
|Comments:||Preferred test to rule-out metachromatic leukodystrophy. This test is not suitable for carrier status detection due to both analytical and unusual genetic variation.
Not reliable in identifying carriers due both to analytical variation and unusual genetic variants. The urine assay should be used to confirm leukocyte results Arylsulfatase A, 24-Hour Urine (90135).
|Rejection Criteria:||Specimen other than whole blood; tube other than specified; gross hemolysis; specimen older than 48 hours of collection.|
|≥ 2.5 U/10(10) cells
Note: Results from this assay may not reflect carrier status because of individual variation of arylsulfatase A enzyme levels. Values between 1.0 and 2.5 are suggestive of the presence of pseudodeficiency gene. Patients with these depressed levels may be phenotypically normal.
Values expected in MLD are ≤ 1.0 U/10(10) cells. Activity between 1.0 U/10(10) cells and 2.5 U/10(10) cells is
considered consistent with depressed but not absent arylsulfatase activity. Carriers or persons with a pseudogene may yield similar results but are unaffected with MLD.