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Q85.1 ICD-10-CM Code: Tuberous sclerosis

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

Coding at a Glance

Tabular directives
2 inclusion terms · 2 Excludes1
Risk adjustment
CMS-HCC V28: 1 category · CMS-HCC V22 category 12 · RxHCC V08 category 22

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 091 — OTHER DISORDERS OF NERVOUS SYSTEM WITH MCC (MDC 01)
  • MS-DRG 092 — OTHER DISORDERS OF NERVOUS SYSTEM WITH CC (MDC 01)
  • MS-DRG 093 — OTHER DISORDERS OF NERVOUS SYSTEM WITHOUT CC/MCC (MDC 01)

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.

Risk Adjustment (CMS-HCC)

Payment categories this diagnosis maps to under CMS-HCC V28, payment year 2026.

  • HCC 23 — Prostate, Breast, and Other Cancers and Tumors

Other models: CMS-HCC V22 HCC 12 · RxHCC V08 HCC 22

Risk scores depend on the enrollee's full accepted diagnosis set and segment; a category mapping alone does not determine payment.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for Q85.1 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 Q85.1 itself; “inherited from” names the category or block whose note applies here.

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Bourneville's disease
  • Epiloia

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).

  • ataxia telangiectasia Louis-Bar
  • familial dysautonomia Riley-Day

Coder workflow for Q85.1

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

Before you code Q85.1

  1. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with Q85.1. 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 Q85.1’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.

Consider Q85.1. 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).

Official instructions as workflow

  • Excludes1 — check before selecting Q85.1(2 notes)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with Q85.1: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

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

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: Both the condition Q85.1 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

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

Tuberous sclerosis is a billable ICD-10-CM diagnosis code (Q85.1).

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

Indexed Clinical Terms (12)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Verify Before Coding

  • CC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

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

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 8 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 3 MS-DRGs: DRG 091 (MDC 01), DRG 092 (MDC 01), DRG 093 (MDC 01).

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

Clinical classification (AHRQ CCSR):MAL010 — Other specified and unspecified congenital anomalies (default).

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

Related Codes

Same clinical process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

Q85.81 — PTEN hamartoma tumor syndrome, Q85.82 — Other Cowden syndrome, Q85.83 — Von Hippel-Lindau syndrome, Q85.89 — Other phakomatoses, not elsewhere classified, Q85.9 — Phakomatosis, unspecified, Q89.7 — Multiple congenital malformations, not elsewhere classified, Q89.9 — Congenital malformation, unspecified

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Prostate, Breast, and Other Cancers and Tumors) for risk-adjusted payment.

D43.8 — Neoplasm of uncertain behavior of other specified parts of central nervous system, D43.9 — Neoplasm of uncertain behavior of central nervous system, unspecified, D44.3 — Neoplasm of uncertain behavior of pituitary gland, D44.4 — Neoplasm of uncertain behavior of craniopharyngeal duct, D44.5 — Neoplasm of uncertain behavior of pineal gland, D44.6 — Neoplasm of uncertain behavior of carotid body, D44.7 — Neoplasm of uncertain behavior of aortic body and other paraganglia, D45 — Polycythemia vera, D47.3 — Essential (hemorrhagic) thrombocythemia, D49.6 — Neoplasm of unspecified behavior of brain, Q85.00 — Neurofibromatosis, unspecified, Q85.01 — Neurofibromatosis, type 1, Q85.02 — Neurofibromatosis, type 2, Q85.03 — Schwannomatosis, Q85.09 — Other neurofibromatosis, Q85.81 — PTEN hamartoma tumor syndrome, Q85.82 — Other Cowden syndrome, Q85.83 — Von Hippel-Lindau syndrome, Q85.89 — Other phakomatoses, not elsewhere classified, Q85.9 — Phakomatosis, unspecified, +213 more

Related risk categories

These categories interact through CMS's HCC hierarchy — one can suppress the other's risk-adjustment weight when both are present on a claim.

Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic, Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers, Lung and Other Severe Cancers, Lymphoma and Other Cancers, Bladder, Colorectal, and Other Cancers

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Other specified and unspecified congenital anomalies).

Q83.9 — Congenital malformation of breast, unspecified, Q84.0 — Congenital alopecia, Q84.1 — Congenital morphological disturbances of hair, not elsewhere classified, Q84.2 — Other congenital malformations of hair, Q84.3 — Anonychia, Q84.4 — Congenital leukonychia, Q84.5 — Enlarged and hypertrophic nails, Q84.6 — Other congenital malformations of nails, Q84.8 — Other specified congenital malformations of integument, Q84.9 — Congenital malformation of integument, unspecified, Q85.8 — Other phakomatoses, not elsewhere classified, Q85.81 — PTEN hamartoma tumor syndrome, Q85.82 — Other Cowden syndrome, Q85.83 — Von Hippel-Lindau syndrome, Q85.89 — Other phakomatoses, not elsewhere classified, Q85.9 — Phakomatosis, unspecified, Q86.0 — Fetal alcohol syndrome (dysmorphic), Q86.1 — Fetal hydantoin syndrome, Q86.2 — Dysmorphism due to warfarin, Q86.8 — Other congenital malformation syndromes due to known exogenous causes, +59 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main terms “Nevus”, “Sclerosis, sclerotic”; these codes share that main term but sit in a different category of the Tabular List.

K74.1 — Hepatic sclerosis (liver), K74.2 — Hepatic fibrosis with hepatic sclerosis (liver, with fibrosis), K76.1 — Chronic passive congestion of liver (liver, cardiac), K86.89 — Other specified diseases of pancreas (pancreas), M34.0 — Progressive systemic sclerosis (progressive, systemic), M34.2 — Systemic sclerosis induced by drug and chemical (systemic, drug-induced), M34.81 — Systemic sclerosis with lung involvement (systemic, with, lung involvement), M34.82 — Systemic sclerosis with myopathy (systemic, with, myopathy), M34.83 — Systemic sclerosis with polyneuropathy (systemic, with, polyneuropathy), M34.89 — Other systemic sclerosis (systemic, specified NEC), M34.9 — Systemic sclerosis, unspecified (systemic), N05.1 — Unspecified nephritic syndrome with focal and segmental glomerular lesions (focal and segmental), N26.9 — Renal sclerosis, unspecified (renal), N48.6 — Induration penis plastica (penis), N50.89 — Other specified disorders of the male genital organs (funicular), N83.8 — Other noninflammatory disorders of ovary, fallopian tube and broad ligament (ovary), N85.5 — Inversion of uterus (endometrium), N90.89 — Other specified noninflammatory disorders of vulva and perineum (corpus cavernosum, female), Q38.6 — Other congenital malformations of mouth (mouth, white sponge), Q82.5 — Congenital non-neoplastic nevus (Unna's), +70 more

Contextual Map

Every relationship of Q85.1 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.

Hierarchy

Clinical classification (CCSR)

Risk adjustment (CMS-HCC)

  • HCC 23 — Prostate, Breast, and Other Cancers and Tumors [CMS-HCC]— CMS-HCC V28 · 2026

MS-DRG Grouper

MDC crossing

  • MDC 01 — Diseases and Disorders of the Nervous System[MDC crossing]: “Diseases and Disorders of the Nervous System — 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. 8,892 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries (12)

  • Bourneville's disease[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Disease, diseased, Bourneville (-Brissaud) (tuberous sclerosis)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Disease, diseased, Pringle's (tuberous sclerosis)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Epiloia[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Neurospongioblastosis diffusa[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Nevus, multiplex[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Phakomatosis, Bourneville's[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Pringle's disease (tuberous sclerosis)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • and 4 more

Nearest codes (13)

Change history

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

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
Risk adjustment Official source data
2026 Mid-Year Final ICD-10 Mappings + Model Software (cms.gov/files/zip/2026-midyear-final-icd-10-mappings.zip, 2026-midyear-final-model-software.zip) — CMS-HCC V28, PY2026 mid-year final release 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 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. "Q85.1 — Tuberous sclerosis." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/q85.1-tuberous-sclerosis

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Tuberous sclerosis

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.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to Q85.1 in its code family, with their registry titles.

View all codes in the Q85 family