Ordering Recommendation

Preferred genetic test for individuals of African descent. Use to detect the single most common pathogenic G6PD variant (the A- allele) in individuals of African descent. For initial screening for GP6D deficiency, refer to Glucose-6-Phosphate Dehydrogenase (0080135).

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation
Collect

Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).

Specimen Preparation

Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions

Frozen specimens in glass collection tubes.

Remarks
Stability

Ambient: 72 hours; Refrigerated: 1 week; Frozen: 1 month

Methodology

Polymerase Chain Reaction/Fluorescence Monitoring

Performed

Mon, Thu

Reported

4-10 days

Reference Interval

Interpretive Data

Background Information for Glucose-6-Phosphate Dehydrogenase (G6PD) 2 Mutations:
Characteristics:
  Although G6PD deficiency is usually asymptomatic, it can result in episodic hemolytic anemia triggered by infections, specific foods, and drugs. In newborns, it may be causal for life-threatening acute hemolytic anemia with jaundice. Variants are classified as follows: Class I: severe enzyme deficiency associated with chronic nonspherocytic hemolytic anemia; Class II: severe enzyme deficiency (<10 percent of normal activity); Class III: mild to moderate enzyme deficiency (10-60 percent of normal activity); and Class IV: normal range (>60 percent of normal enzyme activity). G6PD deficiency is best managed by avoiding known environmental triggers. For a list of drugs that may cause adverse reactions in individuals with G6PD deficiency refer to the Clinical Pharmacogenetics Implementation Consortium: https://cpicpgx.org/genes-drugs/.
Incidence:
Highly variable but ranges between 5-30 percent in males of African, Asian, Mediterranean, and Middle Eastern descent
Inheritance:
X-linked.
Cause:
  Hemizygosity for a pathogenic G6PD germline variant in men, and homozygosity or compound heterozygosity in women. Some heterozygous women may be affected due to skewed X-chromosome inactivation.
Variants Tested:
c.376A>G and c.202G>A (A- allele: both variants present in cis; A+ allele: c.376A>G alone; c.202G>A is rarely if ever seen alone).
Clinical Sensitivity:
  Variable; dependent on the country of origin.
Methodology:
  Polymerase Chain Reaction/Fluorescence Monitoring
Analytical Sensitivity and Specificity:
99 percent.
Limitations:
Only the two G6PD gene variants targeted (c.376A>G and c.202G>A) will be detected. This assay cannot determine phase; thus, concurrent detection of c.376A>G and c.202G>A is presumed to reflect the complex A- allele. Diagnostic errors can occur due to rare sequence variations. Interpretation of this test result may be impacted if this patient has had an allogeneic stem cell transplantation.

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the U.S. Food and Drug Administration. This test was performed in a CLIA-certified laboratory and is intended for clinical purposes.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

Compliance Category

Laboratory Developed Test (LDT)

Note

This assay detects the following variants: c.376A>G and c.202G>A in the G6PD gene.

Hotline History

N/A

CPT Codes

81247

Components

Component Test Code* Component Chart Name LOINC
0051671 G6PD Allele 1 21681-2
0051679 G6PD Allele 2 21681-2
0051687 G6PD Mutations Interpretation 94231-8
2001311 G6PD Africa Specimen 66746-9
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.

Aliases

  • G-6-PD Mutations, African Alleles
  • RBC G6PD mutation assay
Glucose-6-Phosphate Dehydrogenase (G6PD) 2 Mutations