Hexosaminidase A and Total Hexosaminidase, Leukocytes

Casandra

Casandra Test Code QD41779Version 1 (DRAFT)

Performing Lab

Lab Quest DiagnosticsLab Test ID 34842CPT Code 83080

Hexosaminidase A and Total Hexosaminidase, Leukocytes

Clinical Use

Use

Used for diagnosis and carrier testing of Tay‑Sachs disease (deficiency of Hexosaminidase A due to HEXA gene variants) and Sandhoff disease (deficiency of both Hexosaminidase A and B due to HEXB gene variants) in leukocytes. Differentiates between these lysosomal storage disorders via enzyme activity levels in white blood cells. Follow‑up molecular testing may be indicated for clarification of pseudodeficiency alleles or confirmation. Appropriate for males and pregnant or nonpregnant females.

Special Instructions

Specimen must be collected in ACD (yellow‑top) tube and arrive within specified stability window; draw Monday through Thursday only (not before a holiday). New York state clients require documentation of informed consent as indicated on the requisition or electronic order. Testing is performed one or two days per week (semi‑automated heat inactivation fluorometric method).

Limitations

Specimen cannot be frozen; gross hemolysis may lead to rejection. The assay may not detect rare variants or carrier states accurately without follow‑up molecular testing. Not FDA approved; performance characteristics established under CLIA. Pediatric reference ranges differ by age group.

Test Details

Methodology

Immunoassay (Multiplex Protein Panel)

Biomarkers

Hexosaminidase Percent A

Analyte

Hexosaminidase Percent A • Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

Hexosaminidase Total

Analyte

Hexosaminidase Total • Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

LOINC Codes

Order Codes

87544-3

Result Codes

24075-4
23825-3
59462-2
18771-6

Result Turnaround Time

2-6 days

Specimen

Whole Blood

Volume

6 mL

Minimum Volume

5 mL

Container

ACD (yellow‑top) tube

Collection Instructions

Draw blood in ACD Solution A or B yellow‑top tube; send 6 mL refrigerated, with cold packs; keep cool, do not freeze; draw Monday through Thursday only and not the day before a holiday; package as close to shipping time as possible.