ICD-10 Diagnosis Code for Ordering G6PD Testing
The appropriate ICD-10 code for ordering a G6PD test depends on the clinical indication, but the most commonly used codes are D55.0 (anemia due to G6PD deficiency) for suspected deficiency, Z13.0 (encounter for screening for diseases of the blood and blood-forming organs) for screening purposes, or codes related to the precipitating condition such as hyperbilirubinemia (P59.9) in neonates or drug-induced hemolysis.
Clinical Scenarios and Appropriate Coding
Neonatal Hyperbilirubinemia
- P59.9 (Neonatal jaundice, unspecified) is appropriate when ordering G6PD testing in newborns with significant hyperbilirubinemia, as G6PD-deficient infants may develop sudden increases in total serum bilirubin and require intervention at lower levels 1.
- G6PD levels can be falsely elevated in the presence of hemolysis in the newborn period, potentially obscuring the diagnosis, so repeat testing at 3 months may be necessary if deficiency is strongly suspected 1.
Pre-Treatment Screening
- Z13.0 (Encounter for screening for diseases of the blood and blood-forming organs) is appropriate when screening patients before initiating oxidant drugs 2.
- Screening for G6PD deficiency is strongly recommended upon entry into care or before starting therapy with oxidant drugs (dapsone, primaquine, sulfonamides) in patients with predisposing racial or ethnic backgrounds including African American, Mediterranean, or Southeast Asian descent 2.
Drug-Induced Hemolysis
- D59.2 (Drug-induced nonautoimmune hemolytic anemia) is appropriate when G6PD testing is ordered to evaluate acute hemolytic anemia following exposure to known oxidative medications 3.
- Symptoms of acute hemolysis include anemia, fatigue, back or abdominal pain, jaundice, and hemoglobinuria 3.
Methemoglobinemia Management
- D74.9 (Methemoglobinemia, unspecified) is appropriate when G6PD testing is needed before methylene blue administration 4.
- All patients should ideally be tested for G6PD deficiency before methylene blue therapy, as methylene blue is contraindicated in G6PD deficiency and can cause severe hemolytic anemia and paradoxically worsen methemoglobinemia 4.
- In emergency situations where immediate testing is unavailable, a family history of G6PD deficiency should be sought before instituting methylene blue therapy 4.
Tumor Lysis Syndrome
- E88.3 (Tumor lysis syndrome) is appropriate when ordering G6PD screening before rasburicase administration 5.
- Rasburicase is contraindicated in patients with known G6PD deficiency, particularly those of African American, Mediterranean, or Southeast Asian descent 5.
- Screening should include thorough history of prior drug-induced hemolytic anemia, ethnic background, and available semiquantitative laboratory tests, with definitive testing including measurement of RBC NADPH formation recommended 5.
Malaria Treatment
- B50.9 (Plasmodium falciparum malaria, unspecified) or B51.9 (Plasmodium vivax malaria without complication) when ordering G6PD testing before primaquine or tafenoquine for radical cure 6.
- Testing for quantitative G6PD is required before tafenoquine (do not use if <70% activity) 6.
- For those with intermediate G6PD deficiency (>30% to <70%) and non-Mediterranean variant (A-), weekly primaquine with close monitoring for hemolysis may be considered 6.
Important Coding Considerations
Suspected vs. Confirmed Deficiency
- D55.0 (Anemia due to glucose-6-phosphate dehydrogenase deficiency) should only be used when G6PD deficiency is documented or highly suspected based on clinical presentation 3.
- For initial screening without clinical suspicion, Z13.0 is more appropriate 2.
Common Pitfalls to Avoid
- Do not use D55.0 for routine pre-treatment screening in asymptomatic patients without clinical evidence of deficiency, as this may be considered inappropriate coding.
- When G6PD testing is ordered as part of a broader hemolytic anemia workup, D59.9 (Acquired hemolytic anemia, unspecified) may be more appropriate until the specific cause is identified.
- Remember that G6PD deficiency affects approximately 400 million people worldwide and is the most common enzyme deficiency in humans, making appropriate screening and coding essential 3.