ICD-10 Code A51.5 – Early syphilis, latent (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A51.5 – Early syphilis, latent
What it is
A51.5 identifies early syphilis in the latent stage, meaning the infection is present but there are no symptoms or visible lesions. You use it when documentation confirms latent syphilis within the early period.
Clinical signs
Clinical features vary; refer to documentation. Latent syphilis has no clinical signs, but the diagnosis is supported by positive serology and a history consistent with recent infection.
When to use this code
Use A51.5 when the provider documents early latent syphilis, including cases found on screening or follow-up after a recent primary or secondary infection. It also fits when the patient has no symptoms and the record specifically states early latent disease. Check documentation if the stage is unclear.
Do not use for
Do not use this code for primary, secondary, or tertiary syphilis, or for latent syphilis when the stage is not identified. If the chart only says “syphilis” or “positive test,” check documentation.
Coding tip
Code the stage exactly as documented; if “early latent” is not stated, do not assume A51.5.