What N12 covers · when clinicians use it
ICD-10 code N12 identifies Tubulo-interstitial nephritis, not specified as acute or chronic in the U.S. ICD-10-CM clinical and billing record set. It sits within the Genitourinary System chapter (N00–N99), the section that groups related diagnoses so providers, payers, and public-health agencies report them consistently. Clinicians and medical coders apply N12 when an encounter's findings match the Tubulo-interstitial nephritis, not specified as acute or chronic description, attaching it to the patient record so downstream insurance claims, payer audits, quality reporting, and epidemiological surveillance all reference the same standardized diagnosis. The ICD-10-CM is maintained by the Centers for Medicare & Medicaid Services and the CDC's National Center for Health Statistics, with an updated official code set released each U.S. fiscal year — always verify N12 against the current CMS/CDC release and your payer's documentation guidance before final use. This page summarizes documentation context for N12 and is a coding reference, not clinical, diagnostic, or billing advice.
N12 refers to Tubulo-interstitial nephritis, not specified as acute or chronic, a group of disorders affecting the renal tubules and interstitial tissue, caused by infections, toxins, obstructions, or systemic diseases, often leading to impaired kidney function.
Symptoms
- Fever and flank pain – Classic signs of acute pyelonephritis (N10)
- Recurrent urinary tract infections – Seen in chronic nephritis (N11)
- Hematuria and proteinuria – Common across tubulo-interstitial nephritis cases (N12, N15)
- Hydronephrosis and urinary retention – Due to obstructive uropathy (N13)
- History of nephrotoxin exposure – Seen in drug- or metal-induced nephritis (N14)
Diagnosis
Diagnosis of Tubulo-interstitial nephritis, not specified as acute or chronic includes urinalysis, urine culture, kidney function tests, imaging studies (ultrasound, CT scan), and sometimes renal biopsy to assess the extent of tubular and interstitial involvement.
ICD10 Code Usage
ICD10 code N12 is used by nephrologists, urologists, internists, and infectious disease specialists to document and manage acute and chronic tubulo-interstitial kidney diseases, guide antimicrobial therapy, surgical interventions, or manage chronic kidney disease progression.
Related Codes
- N10 – Acute pyelonephritis
- N11 – Chronic tubulo-interstitial nephritis
- N13 – Obstructive and reflux uropathy
- N14 – Drug- and heavy-metal-induced tubulo-interstitial and tubular conditions
- N15 – Other renal tubulo-interstitial diseases
- N16 – Renal tubulo-interstitial disorders in diseases classified elsewhere
FAQs
Q1: What is ICD10 code N12?
A: It refers to Tubulo-interstitial nephritis, not specified as acute or chronic, covering infections, toxic injuries, obstructive issues, and systemic tubulo-interstitial disorders affecting kidney health.
Q2: How does obstructive uropathy (N13) cause kidney damage?
A: Urine backflow increases pressure in the kidneys, impairing function and potentially leading to hydronephrosis and chronic kidney disease.
Q3: What toxins commonly cause drug-induced nephritis (N14)?
A: NSAIDs, antibiotics like aminoglycosides, contrast dyes, lithium, and heavy metals like lead and mercury.
Q4: What differentiates acute (N10) from chronic tubulo-interstitial nephritis (N11)?
A: Acute cases present suddenly with infection signs, while chronic cases develop gradually with scarring and progressive renal impairment.
Q5: How are tubulo-interstitial disorders treated?
A: Treatment depends on cause — antibiotics for infections, withdrawal of nephrotoxic drugs, relieving obstructions, corticosteroids in autoimmune cases, and supportive care for kidney function.
Conclusion
ICD10 code N12 facilitates early identification and precise management of Tubulo-interstitial nephritis, not specified as acute or chronic, helping prevent irreversible kidney damage and improving outcomes through targeted therapies and intervention strategies.