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Test Code LAB1232542 Glucose-6-Phosphate Dehydrogenase (G6PD) Full Gene Sequencing, Varies

Important Note

Mayo code is G6PDZ


Ordering Guidance


For initial or time-sensitive screening for glucose-6-phosphate dehydrogenase deficiency, order G6PD1 / Glucose 6-Phosphate Dehydrogenase Enzyme Activity, Blood.



Necessary Information


Include physician name and phone number with the specimen.



Specimen Required


Submit only 1 of the following specimens:

 

Specimen Type: Whole blood

Container/Tube:

Preferred: Lavender top (EDTA) or yellow top (ACD)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send whole blood specimen in original tube. Do not aliquot.

Specimen Stability Information: Ambient (preferred) 9 days/Refrigerated 30 days

 

Specimen Type: Saliva

Patient Preparation: Patient should not eat, drink, smoke, or chew gum 30 minutes prior to collection.

Supplies: Saliva Swab Collection Kit (T786)

Specimen Volume: 1 Swab

Collection Instructions: Collect and send specimen per kit instructions.

Specimen Stability Information: Ambient 30 days

 


Forms

1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing (Spanish) (T826)

2. If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-Therapeutics Test Request (T831)

-Benign Hematology Test Request Form (T755)

Useful For

Genetic test for individuals at high risk for glucose-6-phosphate dehydrogenase (G6PD) deficiency

 

Aiding in the diagnosis of G6PD deficiency

 

Determining G6PD deficiency status in individuals with inconclusive or unexpected phenotyping results

 

Differentiation of heterozygotes with skewed X-inactivation from homozygotes and compound heterozygotes

 

Definitive diagnosis of carrier status

 

Evaluation of neonates with unexplained jaundice

 

Identifying individuals at risk of drug-induced acute hemolytic anemia related to G6PD deficiency

Genetics Test Information

This test is for molecular sequencing of the G6PD gene and does not assess glucose-6-phosphate dehydrogenase (G6PD) enzyme activity. Enzymatic testing may be suggested as follow-up to this assay. For G6PD enzyme testing order G6PD1 / Glucose 6-Phosphate Dehydrogenase Enzyme Activity, Blood.

 

G6PD deficiency is a common X-linked condition, estimated to affect up to 500 million people worldwide. Both male and female patients may be impacted due to how common G6PD deficiency is in the population.

 

Acute hemolytic anemia (AHA) can be triggered in individuals with G6PD deficiency by fava beans, several types of medications (including rasburicase, dapsone-containing combinations of antimalarial drugs, and methylene blue), and infection. Less commonly, chronic congenital nonspherocytic hemolytic anemia (CNSHA) may occur in severe forms of G6PD deficiency.

 

US Food and Drug Administration labeling and Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines recommend that G6PD testing be undertaken in high-risk populations before prescribing drugs known to cause AHA. Knowing a patient's genotype is generally sufficient to avoid contraindicated drugs, but follow-up with the phenotyping (enzyme) assay may be necessary to clarify results in some cases.

 

This test involves full gene sequencing of all exons and exon/intron boundaries of the G6PD gene. A comprehensive interpretation will be provided including congenital and pharmacogenomic implications of results. Testing should be considered before prescribing medication associated with hemolysis in individuals with G6PD deficiency.

Reporting Name

G6PD Full Gene Sequencing, V

Specimen Type

Varies

Specimen Minimum Volume

Blood: 0.45 mL
Saliva: See Specimen Required

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies

Reject Due To

  All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Reference Values

An interpretive report will be provided.

Day(s) Performed

Monday, Wednesday

Report Available

3 to 7 days

Specimen Retention Time

Whole blood/Saliva: 2 weeks; Extracted DNA: 3 months

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

81249

LOINC Code Information

Test ID Test Order Name Order LOINC Value
G6PDZ G6PD Full Gene Sequencing, V 94231-8

 

Result ID Test Result Name Result LOINC Value
618837 G6PD Phenotype 47998-0
618838 Result Details 82939-0
618839 Interpretation 69047-9
618840 Additional Information 48767-8
618841 Method 85069-3
618842 Disclaimer 62364-5
618843 Reviewed By 18771-6