Davis's Lab & Diagnostic Tests
Hexosaminidase Testing
To view the entire topic, please log in or purchase a subscription.
Nursing Central is an 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:
-- The first section of this topic is shown below --
General
Synonym/Acronym:
TSD (Tay-Sachs disease) testing.
Rationale
To assist in diagnosing Tay-Sachs and Sandhoff 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.
| Plasma Enzyme Assay Conventional Units | Plasma Enzyme Assay SI Units (Conventional Units × 0.0167) | ||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Hexosaminidase Total | 589–955 nmol/hr/mL | 9.83–15.98 nmol/hr/mL | |||||||||||||||||||||||||||||||||||||||
| Hexosaminidase A | 55%–76% of total hexosaminidase | 55%–76% of total hexosaminidase | |||||||||||||||||||||||||||||||||||||||
| Whole blood leukocyte assay: greater than 62% | Molecular assay: Negative for HEXA gene mutations | Molecular assay: Negative for HEXB variants | |||||||||||||||||||||||||||||||||||||||
| Methods vary, reference ranges vary; the reference range and interpretive summary provided in the laboratory report should be used to properly evaluate results. Carrier values are approximately half of the expected normal values. | |||||||||||||||||||||||||||||||||||||||||
Critical Findings and Potential Interventions
N/A
-- To view the remaining sections of this topic, please log in or purchase a subscription --
General
Synonym/Acronym:
TSD (Tay-Sachs disease) testing.
Rationale
To assist in diagnosing Tay-Sachs and Sandhoff 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.
| Plasma Enzyme Assay Conventional Units | Plasma Enzyme Assay SI Units (Conventional Units × 0.0167) | ||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Hexosaminidase Total | 589–955 nmol/hr/mL | 9.83–15.98 nmol/hr/mL | |||||||||||||||||||||||||||||||||||||||
| Hexosaminidase A | 55%–76% of total hexosaminidase | 55%–76% of total hexosaminidase | |||||||||||||||||||||||||||||||||||||||
| Whole blood leukocyte assay: greater than 62% | Molecular assay: Negative for HEXA gene mutations | Molecular assay: Negative for HEXB variants | |||||||||||||||||||||||||||||||||||||||
| Methods vary, reference ranges vary; the reference range and interpretive summary provided in the laboratory report should be used to properly evaluate results. Carrier values are approximately half of the expected normal values. | |||||||||||||||||||||||||||||||||||||||||
Critical Findings and Potential Interventions
N/A
There's more to see -- the rest of this topic is available only to subscribers.
