R94 ICD-10-CM Code: Abnormal results of function studies

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for R94 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 R94 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for R94

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

Before you code R94

1. R94 is not reportable as written. Select the more specific code beneath it that the documentation supports. Codes are reported to the highest level of specificity the classification provides (Guidelines I.B.2).

   ReviewR94.0, R94.1, R94.2, R94.3, R94.4, R94.5, R94.6, R94.7, R94.8

   See the relationships section · Guide: How to choose an ICD-10-CM code →

2. Check whether an established diagnosis that explains this sign or symptom is documented. If one is, review whether the documented diagnosis changes the coding pathway: a symptom that is integral to a confirmed diagnosis is not reported separately, while one not routinely associated with it may be. Signs and symptoms are reported when no definitive diagnosis is established (Guidelines I.B.4, I.B.5, I.B.6, I.C.18.b).

   Guide: Symptom code vs confirmed diagnosis →

3. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with R94. 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 one of the more specific codes beneath R94?
   Yes → Select that code and continue the checks below on its own page.
   No → R94 cannot be reported as written; query for the specificity its subcategory needs.

   ReviewR94.0, R94.1, R94.2, R94.3, R94.4, R94.5, R94.6, R94.7, R94.8

2. Is an established diagnosis that explains this sign or symptom documented?
   Yes → Review whether the documented diagnosis changes the coding pathway: a symptom integral to it is not reported separately.
   No → Continue — the sign or symptom code stands when no definitive diagnosis is established.
3. Does the documentation support a condition named in R94’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.

   ReviewO28

Consider R94. 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 R94(2 notes)

  Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with R94: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

  CompareO28

  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

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.

Don’t confuse R94 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of R94 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• O28— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of abnormal findings on antenatal screening of mother moves the case to O28; the two are not reported together unless documented as unrelated.

  Full comparison: R94 vs O28 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Verify Before Coding

• Not billable as written — a more specific code is required: R94.01, R94.02, R94.09, R94.110, R94.111.

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

Contextual Map

Every relationship of R94 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 R94 with this related code in Claim Check

Hierarchy

• R00-R99 — Chapter 18: Symptoms, Signs and Abnormal Clinical and Laboratory Findings, Not Elsewhere Classified (R00-R99) (R00-R99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R90-R94 — Abnormal findings on diagnostic imaging and in function studies, without diagnosis[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Excludes1

• O28 — Abnormal findings on antenatal screening of mother[Excludes1]: “abnormal findings on antenatal screening of mother (O28.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Nearest codes (29)

• R94.0 — Abnormal results of function studies of central nervous system[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R94.01 — Abnormal electroencephalogram [EEG][Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R94.02 — Abnormal brain scan[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R94.09 — Abnormal results of other function studies of central nervous system[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R94.1 — Abnormal results of function studies of peripheral nervous system and special senses[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R94.11 — Abnormal results of function studies of eye[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R94.110 — Abnormal electro-oculogram [EOG][Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R94.111 — Abnormal electroretinogram [ERG][Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 21 more

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

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

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

Nearest Codes in This Family

Official ICD-10-CM classifications closest to R94 in its code family, with their registry titles.

• R94.0 — Abnormal results of function studies of central nervous system
• R94.01 — Abnormal electroencephalogram [EEG]
• R94.02 — Abnormal brain scan
• R94.09 — Abnormal results of other function studies of central nervous system
• R94.1 — Abnormal results of function studies of peripheral nervous system and special senses
• R94.11 — Abnormal results of function studies of eye
• R94.110 — Abnormal electro-oculogram [EOG]
• R94.111 — Abnormal electroretinogram [ERG]
• R94.112 — Abnormal visually evoked potential [VEP]
• R94.113 — Abnormal oculomotor study
• R94.118 — Abnormal results of other function studies of eye
• R94.12 — Abnormal results of function studies of ear and other special senses
• R94.120 — Abnormal auditory function study
• R94.121 — Abnormal vestibular function study
• R94.128 — Abnormal results of other function studies of ear and other special senses
• R94.13 — Abnormal results of function studies of peripheral nervous system
• R94.130 — Abnormal response to nerve stimulation, unspecified
• R94.131 — Abnormal electromyogram [EMG]
• R94.138 — Abnormal results of other function studies of peripheral nervous system
• R94.2 — Abnormal results of pulmonary function studies
• R94.3 — Abnormal results of cardiovascular function studies
• R94.30 — Abnormal result of cardiovascular function study, unspecified
• R94.31 — Abnormal electrocardiogram [ECG] [EKG]
• R94.39 — Abnormal result of other cardiovascular function study
• R94.4 — Abnormal results of kidney function studies
• R94.5 — Abnormal results of liver function studies
• R94.6 — Abnormal results of thyroid function studies
• R94.7 — Abnormal results of other endocrine function studies
• R94.8 — Abnormal results of function studies of other organs and systems