A18.39 ICD-10-CM Code: Retroperitoneal tuberculosis

A18.39 is the ICD-10-CM diagnosis code for retroperitoneal tuberculosis. This is a tuberculosis infection that affects the retroperitoneal space, which is the area behind the abdominal cavity containing organs like the kidneys and pancreas. It represents an extrapulmonary form of TB that has spread beyond the lungs to this specific anatomical region. A18.39 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering tuberculosis (a15-a19).

A18.39 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

This code requires confirmation of tuberculosis diagnosis with appropriate testing (culture, AFB smear, or molecular testing) and documentation of the retroperitoneal location, often confirmed by imaging studies.