2027 ICD-10-CM Diagnosis Code A36.84Diphtheritic tubulo-interstitial nephropathy
ICD-10-CM Codes›A00–B99›A30-A49›A36
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Not Chronic
A36.84 is a billable ICD-10-CM diagnosis code for diphtheritic tubulo-interstitial nephropathy. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 867 through 869. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 12 closely related codes. Coders also document this condition as acute renal cortical necrosis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections and Nephritis; nephrosis; renal sclerosis.
A36.84 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model. It still risk-adjusts in the ESRD (V21) category 141 for payment year 2027.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
A36.84 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model, but it maps to payment categories in the other CMS models shown below.
Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acute renal cortical necrosis
- Acute tubular necrosis
- Bacterial nephritis
- Diphtheria tubulointerstitial nephropathy
- Diphtheritic renal tubular necrosis
- Toxic acute tubular necrosis
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to A36.84: its own notes plus those printed at Chapter 1. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- diseases generally recognized as communicable or transmissible
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
- carrier or suspected carrier of infectious disease (Z22.-)
- certain localized infections - see body system-related chapters
- infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
- infectious and parasitic diseases specific to the perinatal period (P35-P39)
- influenza and other acute respiratory infections (J00-J22)
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify resistance to antimicrobial drugs (Z16.-)
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name A36.84, its category, or a range that includes it.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Disorder (of) See Also: Disease;
Pyelonephritis See Also: Nephritis, tubulo-interstitial;
diphtheria A36.84
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Diphtheria
a localized infection of mucous membranes or skin caused by toxigenic strains of corynebacterium diphtheriae. it is characterized by the presence of a pseudomembrane at the site of infection. diphtheria toxin, produced by c. diphtheriae, can cause myocarditis, polyneuritis, and other systemic toxic effects.
Patient EducationClinical
Diphtheria
Diphtheria is a serious bacterial infection. You can catch it from a person who has the infection and coughs or sneezes. You can also get infected by coming in contact with an object, such as a toy, that has bacteria on it.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert A36.84 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About A36.84Overview
What is the ICD-10 code for diphtheritic tubulo-interstitial nephropathy?
The ICD-10-CM code for diphtheritic tubulo-interstitial nephropathy is A36.84 (sometimes written as A3684). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is A36.84 (Other diphtheria) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report diphtheritic tubulo-interstitial nephropathy on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does A36.84 group to?
When diphtheritic tubulo-interstitial nephropathy is the principal diagnosis on an inpatient stay, it groups to MS-DRG 867, 869, 868, with relative weights from 0.6784 to 2.1855 depending on complications. Higher weights mean higher Medicare reimbursement.
Is A36.84 a CC or MCC?
CMS lists A36.84 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 12 closely related codes in its exclusion list.
What is the ICD-9 equivalent of A36.84?
Under the General Equivalence Mappings, diphtheritic tubulo-interstitial nephropathy converts to ICD-9-CM 032.89 (diphtheria NEC). The mapping is approximate, so confirm the match fits the documentation.
Does A36.84 risk-adjust for Medicare Advantage payment?
Not for Medicare Advantage: A36.84 maps to no category in the CMS-HCC V28 model. It still risk-adjusts in the ESRD (V21) category 141 (Nephritis).
