ICD-10 Code A36.84 – Diphtheritic tubulo-interstitial nephropathy (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A36.84 – Diphtheritic tubulo-interstitial nephropathy
What it is
This code identifies kidney inflammation affecting the tubules and interstitium as a complication of diphtheria. Use it when the record clearly links renal involvement to diphtheritic infection.
Clinical signs
Clinical features vary; refer to documentation. Supporting records may describe acute kidney injury, abnormal urinalysis, or renal impairment occurring in the setting of diphtheria.
When to use this code
Use A36.84 when the provider documents tubulo-interstitial nephropathy due to diphtheria, or clearly states renal involvement from the infection. It is appropriate for confirmed diphtheritic kidney disease in inpatient, outpatient, or coding abstraction records. Check documentation if the renal diagnosis is nonspecific or the cause is not stated.
Do not use for
Do not use this code for kidney disease without a documented diphtheria cause. If the nephropathy is due to another infection, toxin, or unspecified etiology, code the documented condition instead.
Coding tip
Link the renal diagnosis to diphtheria only when the provider makes that causal connection.