N11.8Other chronic tubulo-interstitial nephritis

N11.8 is the ICD-10-CM diagnosis code for other chronic tubulo-interstitial nephritis. It belongs to category N11 (chronic tubulo-interstitial nephritis), block N10-N16 (renal tubulo-interstitial diseases) and chapter 14 (diseases of the genitourinary system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within N11, choose N11.8 (Other chronic tubulo-interstitial nephritis) only when documentation doesn't support a more specific option: nonobstructive reflux-associated chronic pyelonephritis (N11.0), chronic obstructive pyelonephritis (N11.1) and unspecified (N11.9).

Use an additional code (B95-B97), to identify infectious agent.

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 689 (Kidney and Urinary Tract Infections with MCC, relative weight 1.1415) and DRG 690 (Kidney and Urinary Tract Infections without MCC, relative weight 0.801), in MDC 11 (Diseases and Disorders of the Kidney and Urinary Tract), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 590.01 (chronic pyelonephritis with lesion of renal medullary necrosis).