ICD-10-CM · Chapter 14 · N00-N99
N12 Tubulo-interstitial nephritis, not specified as acute or chronic
Includes
- Interstitial nephritis NOS
- Pyelitis NOS
- Pyelonephritis NOS
Excludes 1 (cannot be coded together)
- calculous pyelonephritis (N20.9)
This category is a complete, billable diagnosis code.
No additional specificity is required — submit N12 directly on claims and documentation without a subcode extension.
Last reviewed: September 2026