Hexosaminidase A and B

Hexosaminidase A and B is a topic covered in the Davis's Lab & Diagnostic Tests.

To view the entire topic, please or purchase a subscription.

Nursing Central is the award-winning, complete mobile solution for nurses and students. Look up information on diseases, tests, and procedures; then consult the database with 5,000+ drugs or refer to 65,000+ dictionary terms. Explore these free sample topics:

Nursing Central

-- The first section of this topic is shown below --

Synonym/Acronym:
TSD (Tay-Sachs disease) testing.

Rationale
To assist in diagnosing Tay-Sachs disease by identifying a hexosaminidase enzyme deficiency.

Patient Preparation
There are no food, fluid, activity, or medication restrictions unless by medical direction.

Normal Findings
Method: Fluorometry for enzyme assay, polymerase chain reaction (PCR)/primer extension for molecular assay.


Enzyme Assay
Total HexosaminidaseConventional UnitsSI Units (Conventional Units × 0.0167)
Noncarrier589–955 nmol/hr/mL9.83–15.95 units/L
Heterozygote465–675 nmol/hr/mL7.77–11.27 units/L
Tay-Sachs homozygoteGreater than 1,027 nmol/hr/mLGreater than 17.15 units/L
Hexosaminidase AConventional UnitsSI Units (Conventional Units × 0.0167)
Noncarrier456–592 nmol/hr/mL or 55–76% of total hexosaminidase7.62–9.88 units/L or 55–76% of total hexosaminidase
Heterozygote197–323 nmol/hr/mL3.29–5.39 units/L
Tay-Sachs homozygote0 nmol/hr/mL0 units/L
Hexosaminidase BConventional UnitsSI Units (Conventional Units × 0.0167)
Noncarrier12–32 nmol/hr/mL0.2–0.54 units/L
Heterozygote21–81 nmol/hr/mL0.35–1.35 units/L
Tay-Sachs homozygoteGreater than 305 nmol/hr/mLGreater than 5.09 units/L

Molecular assay: Negative for HEXA 7 mutations (samples are evaluated for seven specific HEXA gene mutations).

Critical Findings and Potential Interventions
N/A

-- To view the remaining sections of this topic, please or purchase a subscription --