Specimen

Whole Blood

Collection Medium:

Minimum:

Adult Preferred Minimum: 5.0 mL whole blood from 6 mL pink top
  (K2 EDTA) tube. Collect specimen from a fasting patient.

Adult/Pediatric Absolute minimum: 2.0 mL whole blood from 6 mL pink
   top (K2 EDTA) tube. Collect specimen from a fasting patient.

Rejection Criteria:

Specimen cannot be frozen.

Specimen
Instructions:

Patient's age is required on request form for processing.

Analytic Time:

1 week

Reference Range:

Descriptive report

Comments:

This assay is useful for determining the likely genotype when 
quantitative galactose-1-phosphate uridyltransferase (GALT) data 
suggests a GG or DG genotype (a patient with a GG genotype must be on a 
galactose-free diet).

Useful for:
1) Determining the exact biochemical phenotype when quantitative GALT 
(galactose-1-phosphate uridyltransferase (GALT) deficiency suggests a 
GG or DG phenotype

2) A quantitative GALT level is used in addition to the isoelectric 
focusing for accurate interpretation

3) Determining biochemical phenotypes of siblings, when parental 
specimens are co-run for both quantitative and isoelectric focusing 
banding data

There are a variety of biochemical phenotypes in galactosemia and 
quantitative data is only suggestive of the phenotype for a particular 
individual.  An interpretive report is provided.

CAUTIONS:
The phenotype of a neonate can be arrived at with greater confidence 
when the parents' phenotypes are also established.

Since transfusion results in replacement of significant number of red 
cells, the assay should be deferred for 90 days post-transfusion.

Methodology:

Isoelectric Focusing

CPT Code:

82664

See also:
Galactosemia Confirmation Test, Blood

See Additional Information:
Fasting Specimen Requirements