ICD-10 Code B51.9 – Plasmodium vivax malaria without complication (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B51.9 – Plasmodium vivax malaria without complication
What it is
B51.9 identifies malaria caused by Plasmodium vivax when no complication is documented. Use it for an uncomplicated infection rather than severe, recurrent, or mixed malaria.
Clinical signs
Typical findings include fever, chills, headache, sweats, and malaise; clinical features vary, so refer to documentation. Diagnosis is usually supported by malaria testing and species identification.
When to use this code
Use B51.9 when the record names Plasmodium vivax malaria and does not describe complications. This fits outpatient, emergency, or inpatient encounters where the provider documents malaria without severe organ involvement or other specified complication.
Do not use for
Do not use this code if the chart documents complications, severe disease, or another malaria species. Check documentation when the species is unclear or when the note says mixed, recurrent, or complicated malaria.
Coding tip
Verify both the Plasmodium species and the absence of complications before assigning B51.9.