ICD-10 Code A18.39 – Retroperitoneal Tuberculosis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A18.39 – Retroperitoneal tuberculosis
What it is
A18.39 identifies tuberculosis infection involving the retroperitoneum, the space behind the abdominal lining. Use it when documentation specifically states retroperitoneal tuberculosis or a tuberculous process in that location.
Clinical signs
Clinical features vary; refer to documentation. Patients may have nonspecific abdominal or back pain, a retroperitoneal mass, or imaging findings suggesting tuberculous involvement.
When to use this code
Use this code when the provider documents retroperitoneal tuberculosis as the diagnosis, including confirmed or suspected tuberculous involvement of retroperitoneal tissues. It may also fit cases described as tuberculous retroperitoneal disease on imaging or pathology. If the record only says tuberculosis elsewhere, do not assume this site.
Do not use for
Do not use for pulmonary tuberculosis, generalized tuberculosis, or other abdominal TB sites unless the retroperitoneum is clearly documented. Check documentation if the anatomic site is unclear.
Coding tip
Always code the exact anatomic site named in the record; retroperitoneal and peritoneal tuberculosis are not interchangeable.