ICD-10 Code A18 – Tuberculosis of other organs (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A18 – Tuberculosis of other organs
What it is
A18 identifies tuberculosis involving organs or sites other than the lungs. Use it when documentation shows extrapulmonary TB affecting an organ not named by a more specific code.
Clinical signs
Clinical features vary by site and may include chronic inflammation, swelling, pain, or organ-specific dysfunction. Confirmed diagnosis usually depends on documentation of tuberculosis outside the respiratory tract.
When to use this code
Use A18 when the record states TB of an unspecified other organ or when the site is clearly extrapulmonary but not indexed to a more specific code. It is appropriate for confirmed tuberculosis with documentation that does not identify a better anatomic code.
If the chart names a specific organ, verify whether a more detailed ICD-10 code exists before assigning A18. Check documentation for the exact site and any associated manifestations.
Do not use for
Do not use A18 for pulmonary tuberculosis or for extrapulmonary TB with a more specific code available. Do not assign it when the record only says “suspected TB”; check documentation.
Coding tip
Always code the most specific tuberculosis site documented, and use A18 only when the organ involvement is nonspecific or not separately coded.