Galactose-1-phosphate uridyl transferase; quantitative
CPT4 code
Name of the Procedure:
Galactose-1-phosphate uridyl transferase (GALT) Enzyme Activity Assay; Quantitative
Summary
The Galactose-1-phosphate uridyl transferase (GALT) enzyme activity assay is a blood test that measures the activity level of the GALT enzyme. This enzyme is crucial for the proper metabolism of galactose, a type of sugar found in milk and other dairy products.
Purpose
The primary purpose of the GALT enzyme activity assay is to diagnose galactosemia, a rare genetic disorder where the body cannot process galactose properly. Early diagnosis is critical to prevent complications like liver damage, intellectual disability, and cataracts. The test can also be used to monitor individuals diagnosed with galactosemia.
Indications
- Newborns with positive results on routine newborn screening tests for galactosemia.
- Infants and children displaying symptoms such as jaundice, vomiting, poor weight gain, lethargy, or liver enlargement.
- Family history of galactosemia.
- Monitoring the treatment efficacy in individuals diagnosed with galactosemia.
Preparation
No special preparation, such as fasting, is typically required for a GALT enzyme activity assay. However, it’s important to inform the healthcare provider about any medications the patient is currently taking, as some drugs can affect enzyme levels.
Procedure Description
- Sample Collection: A blood sample is drawn from a vein in the arm using a needle.
- Laboratory Analysis: The blood sample is then sent to a laboratory where the activity of the GALT enzyme is measured quantitatively using specialized biochemical methods.
- Anesthesia: No anesthesia or sedation is required for this procedure since it is a simple blood draw.
Duration
The blood draw itself takes just a few minutes. However, lab processing can take several days to a week.
Setting
The blood sample can be collected in a hospital, outpatient clinic, or a specialized lab setting.
Personnel
- Phlebotomist: Collects the blood sample.
- Laboratory Technician/Scientist: Performs the enzyme activity analysis in the laboratory.
Risks and Complications
- Common: Minor discomfort or bruising at the site where the blood sample is drawn.
- Rare: Infection at the puncture site, excessive bleeding.
Benefits
- Diagnosis: Provides a definitive diagnosis of galactosemia.
- Management: Helps in planning dietary and medical management to prevent complications associated with galactosemia.
- Monitoring: Facilitates ongoing monitoring of enzyme activity in known patients.
Recovery
There is no significant recovery period required after a blood draw. The patient can resume normal activities immediately.
Alternatives
- DNA Analysis: Genetic testing to identify mutations in the GALT gene.
- Galactose-1-phosphate levels: Measuring levels in red blood cells can also help diagnose galactosemia.
- Pros and Cons: Genetic testing can confirm a specific mutation but may be more expensive. Measuring galactose-1-phosphate levels is useful but may not differentiate between different forms of galactosemia.
Patient Experience
The patient may feel a brief sting or pinch during the blood draw but should not experience significant pain. If necessary, pain management techniques like topical anesthetics can be applied before the procedure to minimize discomfort. After the draw, it’s advisable to keep the bandage on for a few hours to prevent bleeding.