Is N12 a billable ICD-10-CM code?

Yes. N12 is a billable, specific ICD-10-CM code and is valid for submission on a claim.

Where does N12 sit in the tabular list?

Diseases of the genitourinary system (N00-N99), in the block Renal tubulo-interstitial diseases (N10-N16).

What cannot be coded together with N12?

N12 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.

N12

N12 — Tubulo-interstitial nephritis, not specified as acute or chronic

Billable / specific codeICD-10-CM

N12 is a billable, specific ICD-10-CM code for tubulo-interstitial nephritis, not specified as acute or chronic. It is valid for submission on a claim.

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

calculous pyelonephritis (N20.9)

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

Interstitial nephritis NOS
Pyelitis NOS
Pyelonephritis NOS

Other codes that can never be billed with N12

These codes carry an Excludes1 note pointing at N12. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading N12 alone.

N05Unspecified nephritic syndrome

Risk adjustment

N12 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Medicare coverage

N12 is named in 2 Medicare coverage policies — 2 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

A55336Billing and Coding: Retroperitoneal Ultrasound
A56421Billing and Coding: CT of the Abdomen and Pelvis

How N12 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to N12.

Pyonephritis
Nephritis, nephritic›antitubular basement membrane NEC(tubulo-interstitial)
Nephritis, nephritic›tubulo-interstitial(in)
Pyelonephritis›nonobstructive
Disease, diseased›antiglomerular basement membrane antibody›tubulo-interstitial nephritis
Disease, diseased›renal›with›interstitial nephritis

Questions about N12

Is N12 a billable ICD-10-CM code?: Yes. N12 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does N12 sit in the tabular list?: Diseases of the genitourinary system (N00-N99), in the block Renal tubulo-interstitial diseases (N10-N16).
What cannot be coded together with N12?: N12 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.