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N16 ICD-10-CM Code: Renal tubulo-interstitial disorders in diseases classified elsewhere

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
3 inclusion terms · 11 Excludes1 · 9 code-first instructions

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, Appendix B.

  • MS-DRG 698 — OTHER KIDNEY AND URINARY TRACT DIAGNOSES WITH MCC (MDC 11)
  • MS-DRG 699 — OTHER KIDNEY AND URINARY TRACT DIAGNOSES WITH CC (MDC 11)
  • MS-DRG 700 — OTHER KIDNEY AND URINARY TRACT DIAGNOSES WITHOUT CC/MCC (MDC 11)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for N16 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on N16 itself; “inherited from” names the category or block whose note applies here.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • pyelonephritis

Source: inherited from N10-N16

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Pyelonephritis
  • Tubulo-interstitial nephritis

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Code First

Underlying conditions that must be sequenced before this code.

Coder workflow for N16

MedCoder structured workflow — derived from this code’s own official record

Before you code N16

  1. N16 is a manifestation code (“in diseases classified elsewhere”). Confirm the underlying condition is documented and sequence it first; a manifestation code is not reported as the first-listed or principal diagnosis. The etiology/manifestation convention (Guidelines I.A.13).

    See the official tabular notes · Guide: Manifestation codes and Code First sequencing →

  2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with N16. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

    See the official tabular notes

Choose the right path

  1. Does the documentation support a condition named in N16’s Excludes1 note?
    Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
    No → Continue.

    ReviewA36.84, B37.49, E72.04, A02.25, D86.84, M35.04

  2. Is the underlying (etiologic) condition the Code First note names documented?
    Yes → Sequence the underlying condition first, then N16.
    No → A manifestation code needs its underlying condition — query before reporting it.

    ReviewD89.1, E74.0, C90.0, E83.01

Consider N16. Then confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
The underlying (etiologic) condition
Named in the Code First note; sequenced before this code when documented (Guidelines I.A.13).

Official instructions as workflow

  • Excludes1 — check before selecting N16(11 notes)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with N16: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareA36.84, B37.49, E72.04, A02.25, D86.84, M35.04

    See the official tabular notes · Guidelines I.A.12.a

  • Code First — sequencing check(9 notes)

    Coding workflow: Check whether the underlying or etiologic condition the note names is documented. When it is, sequence it before N16. Do not add an underlying condition the record does not document.

    ReviewD89.1, E74.0, C90.0, E83.01

    See the official tabular notes · Guidelines I.A.13

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Code Overview

Renal tubulo-interstitial disorders in diseases classified elsewhere is a billable ICD-10-CM diagnosis code (N16).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Coding Notes

MedCoder editorial — not official ICD-10-CM text; reviewed against the cited source

What this code means

N16 is the manifestation code for renal tubulo-interstitial disorders — its inclusion terms are pyelonephritis and tubulo-interstitial nephritis — occurring in a disease classified elsewhere. Like J17 and J99, it names the kidney finding while the underlying systemic disease carries the claim.

Coding guidance

  • Sequence the underlying disease first, from the code’s own Code First list: brucellosis (A23.0-A23.9), cryoglobulinemia (D89.1), glycogen storage disease (E74.0-), leukemia (C91-C95), lymphoma, multiple myeloma (C90.0-), sepsis (A40.0-A41.9), or Wilson’s disease (E83.01).
  • The Medicare Code Editor carries N16 on its manifestation-code list: the underlying condition is sequenced first, so N16 cannot be the principal diagnosis on an inpatient claim.
  • A separate set of diseases is Excludes1 rather than Code First — diphtheria, candidiasis, cystinosis, salmonella infection, sarcoidosis, Sjögren syndrome, systemic lupus erythematosus, and toxoplasmosis each have a dedicated combination code for the same kidney finding, and those are used instead of N16.

Decision-rule scenarios

Documentation: A patient with documented multiple myeloma has tubulo-interstitial nephritis attributed to it.

Coding question: How is this sequenced?

Rule: Multiple myeloma (C90.0-) is sequenced first per the Code First note, followed by N16. The deciding element is that myeloma appears on N16’s Code First list.

Documentation: The record documents pyelonephritis in a patient with systemic lupus erythematosus.

Coding question: Does N16 apply?

Rule: No — lupus-related pyelonephritis and tubulo-interstitial nephritis is on N16’s Excludes1 list with its own combination code (M32.15). The deciding element is which disease is documented: Code First list and Excludes1 list send the same kidney finding down two different paths.

Scenarios state the decision rule, not a code assignment — code selection always follows the provider's documentation and the ICD-10-CM Official Guidelines.

Documentation checklist

  • The underlying systemic disease, named precisely enough to place it on the Code First or the Excludes1 list.
  • That the kidney finding is attributed to that disease rather than independently caused.

Codes are assigned from provider documentation; a coder never infers a diagnosis.

Common mistakes

  • Reporting N16 without the underlying disease coded first.
  • Using N16 as an inpatient principal diagnosis — the MCE manifestation edit requires the etiology first.
  • Using N16 for a disease on its Excludes1 list (lupus, Sjögren’s, sarcoidosis, cystinosis, candidiasis, salmonella, toxoplasmosis, diphtheria), each of which has its own combination code.

Written and reviewed by MedCoder against the official ICD-10-CM files; educational, not medical or billing advice. The official tabular notes and guidelines above take precedence in every case.

Verify Before Coding

  • Principal-diagnosis restriction. This is a manifestation code: the Medicare Code Editor requires the underlying condition (etiology) to be sequenced first, with this code reported after it.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name N16 or its code family, from the CMS ICD-10-CM tabular instructional notes and the CMS ICD-10-CM Index to Diseases and Injuries. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Excludes1 note: N08 — Glomerular disorders in diseases classified elsewhere.

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 1 Index etiology/manifestation pair: T86.91 — Unspecified transplanted organ and tissue rejection.

The ICD-10-CM Index lists these etiology codes with this code in brackets — the manifestation, reported second.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 3 MS-DRGs: DRG 698 (MDC 11), DRG 699 (MDC 11), DRG 700 (MDC 11).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):GEN001 — Nephritis; nephrosis; renal sclerosis.

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Principal diagnosis restriction (Medicare Code Editor)

Manifestation code — the underlying condition is sequenced first.

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Nephritis; nephrosis; renal sclerosis).

N07.4 — Hereditary nephropathy, not elsewhere classified with diffuse endocapillary proliferative glomerulonephritis, N07.5 — Hereditary nephropathy, not elsewhere classified with diffuse mesangiocapillary glomerulonephritis, N07.6 — Hereditary nephropathy, not elsewhere classified with dense deposit disease, N07.7 — Hereditary nephropathy, not elsewhere classified with diffuse crescentic glomerulonephritis, N07.8 — Hereditary nephropathy, not elsewhere classified with other morphologic lesions, N07.9 — Hereditary nephropathy, not elsewhere classified with unspecified morphologic lesions, N07.A — Hereditary nephropathy, not elsewhere classified with C3 glomerulonephritis, N07.B — Hereditary nephropathy, not elsewhere classified with APOL1-mediated kidney disease [AMKD], N08 — Glomerular disorders in diseases classified elsewhere, N14.0 — Analgesic nephropathy, N14.1 — Nephropathy induced by other drugs, medicaments and biological substances, N14.11 — Contrast-induced nephropathy, N14.19 — Nephropathy induced by other drugs, medicaments and biological substances, N14.2 — Nephropathy induced by unspecified drug, medicament or biological substance, N14.3 — Nephropathy induced by heavy metals, N14.4 — Toxic nephropathy, not elsewhere classified, N15.0 — Balkan nephropathy, N15.8 — Other specified renal tubulo-interstitial diseases, N15.9 — Renal tubulo-interstitial disease, unspecified, N26.9 — Renal sclerosis, unspecified, +112 more

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

Blood Glucose Test, Gamma-glutamyl Transferase (GGT) Test

Contextual Map

Every relationship of N16 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run N16 with these 17 related codes in Claim Check

Hierarchy

Excludes1 (15)

Code First (32)

Referenced by Excludes1 notes

Referenced by Index etiology/manifestation pairs

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 11 — Diseases and Disorders of the Kidney and Urinary Tract[MDC crossing]: “Diseases and Disorders of the Kidney and Urinary Tract — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 3,574 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Common coding questions

Can N16 be the principal diagnosis?

No — the Medicare Code Editor carries N16 on its manifestation-code list, so the underlying disease is sequenced first and N16 cannot be principal on an inpatient claim. The underlying disease is sequenced first, from its Code First list: brucellosis, cryoglobulinemia, glycogen storage disease, leukemia, lymphoma, multiple myeloma, sepsis, or Wilson’s disease.

Is N16 used for lupus or Sjögren’s nephritis?

No — pyelonephritis and tubulo-interstitial nephritis in systemic lupus erythematosus (M32.15), Sjögren syndrome (M35.04), sarcoidosis (D86.84), cystinosis, candidiasis, salmonella infection, toxoplasmosis and diphtheria are all Excludes1, each with its own combination code.

What conditions does N16 itself name?

Its inclusion terms are pyelonephritis and tubulo-interstitial nephritis — the kidney finding, reported as a manifestation of whichever underlying disease the Code First note names.

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary, coding notes, decision checklist and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "N16 — Renal tubulo-interstitial disorders in diseases classified elsewhere." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/n16-renal-tubulo-interstitial-disorders-in-diseases-classified-elsewhere

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Renal tubulo-interstitial disorders in diseases classified elsewhere

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.