Galactosemia Reflex, Blood

Casandra

Casandra Test Code MC47575Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID GCTCPT Codes 81406, 82775

Galactosemia Reflex, Blood

Clinical Use

Use

This test is preferred for the diagnosis, carrier detection, and determination of genotype for galactose-1-phosphate uridyltransferase deficiency, the most common cause of galactosemia. It helps differentiate Duarte variant galactosemia from classic galactosemia and confirms results of newborn screening programs. It is routinely used for evaluating possible diagnosis of galactosemia, carrier screening, and follow-up of abnormal newborn screening results.

Special Instructions

This test begins with quantitative analysis of the GALT enzyme. If GALT enzyme activity is below a certain threshold, full gene sequencing is performed as a reflex test. Patient's age is required for the test order and specific specimen tubes are preferred for accurate results.

Limitations

This assay will not reliably detect deletions-insertions of 40 or more base pairs, including Alu insertions and other repetitive elements. Low-level mosaic variants may not be identified accurately. Additionally, it is not designed to distinguish between somatic and germline variants, potentially requiring additional testing. The interpretation of test results should account for clinical findings, family history, and other lab data to minimize errors.

Test Details

New York Approved