G6PD Deficiency Screening and Management
Recommended Screening Approach
- Qualitative screening for G6PD deficiency is recommended upon entry into care or before starting therapy with oxidant drugs in patients with predisposing racial or ethnic backgrounds (Mediterranean, African, Indian, or Southeast Asian descent) 1, 2
Test Selection Based on Clinical Context
- Qualitative fluorescent spot test is appropriate for detecting severe G6PD deficiency (enzyme activity <10% of normal) in males and homozygous females 1, 2
Critical Clinical Considerations
- Dapsone, primaquine, and sulfonamides are the most common oxidant drugs used in HIV-infected patients that cause hemolysis in G6PD deficiency 1, 2
- Primaquine, rasburicase, and methylthioninium chloride (methylene blue) are contraindicated in G6PD deficiency due to severe hemolytic anemia risk 4
- For P. vivax radical cure, test for quantitative G6PD before prescribing; do not use tafenoquine if activity is <70% 3
- The American College of Physicians and other medical societies recommend avoiding oxidant drugs in patients with G6PD deficiency, particularly those with the Mediterranean variant 1, 2
Variant-Specific Risk Stratification
- Mediterranean variant (Gdmed) causes life-threatening hemolysis and requires strict avoidance of oxidant drugs 1, 2
- African variant (GdA-) produces milder, self-limited hemolysis that may not preclude oxidant drug use with close monitoring 1, 2
- Patients with intermediate G6PD deficiency (30-70% activity) and non-Mediterranean variant can receive weekly primaquine (0.75 mg base/kg for 8 weeks) with close hemolysis monitoring 3