Preferred test for individuals of African descent. Detects the single most common pathogenic G6PD variant (A- allele) in individuals of African descent.
For initial screening for GP6D deficiency, refer to Glucose-6-Phosphate Dehydrogenase (0080135).
- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 1 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics: G6PD deficiency can cause chronic hemolytic anemia, food-, drug- and infection-mediated acute hemolytic anemia, and neonatal jaundice. Most mutations identified to-date have been classified according to the following scheme: Class I - severe enzyme deficiency with chronic non-spherocytic hemolytic anemia (CNSHA); Class II - severe enzyme deficiency with less than 10 percent of the normal activity; Class III - mild to moderate enzyme deficiency (10 to 60 percent of normal activity); and Class IV - very mild to almost normal enzyme activity (greater than 60 percent normal activity with no clinical consequences).
Drug Sensitivities: Adriamycine and other anthracycline chemotherapy agents, Dapsone, Flutamide, Mafenide cream, Methylene blue, Nalidixic acid, Nitrofurantoin, Phenazopyridine, Primaquine, Rasburicase, Sulfacetamide, Sulfamethoxazole, and Sulfanilamide.
Incidence: Varies by ethnicity; 7 in 10 Kurdish Jewish males; 1 in 6 to 10 African American males; 1 in 7 to 9 Arabic males; 1 in 6 to 16 Southeast Asian males.
Inheritance: X-linked recessive.
Cause: Deleterious mutations in only the Glucose-6-Phosphate Dehydrogenase (G6PD) gene.
Mutations Tested: c.376A>G and c.202G>A (A- allele: both mutations present in cis; A+ allele: c.376A>G alone; c.202G>A is rarely if ever seen alone).
Clinical Sensitivity: 99 percent in individuals of African descent.
Methodology: Allele-specific hydrolysis probes (TaqMan) and fluorescent monitoring.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Only the two G6PD gene mutations targeted (c.376A>G and c.202G>A) will be detected; analytical sensitivity may be affected by rare primer or probe site mutations. Diagnostic errors can occur due to rare sequence variations.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|0051671||G6PD Allele 1||21681-2|
|0051679||G6PD Allele 2||21681-2|
|0051687||G6PD Mutations Interpretation||21680-4|
|2001311||G6PD Africa Specimen||31208-2|
- G-6-PD Mutations, African Alleles
- RBC G6PD mutation assay