2026 ICD-10-CM Diagnosis Code R94.6Abnormal results of thyroid function studies

ICD-10-CM Codes›R00–R99›R90-R94›R94

ICD-10-CM R94.6
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

R94.6 is a billable ICD-10-CM diagnosis code for abnormal results of thyroid function studies. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 643 through 645. As a symptom code, it should not be used as a principal diagnosis once a related definitive diagnosis has been established. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Abnormal findings without diagnosis.

Code Identity

ICD-10-CM Code
R94.6
Billable Status
Yes — Valid for Submission
Code Describes
Abnormal results of thyroid function studies
Short Description
Abnormal results of thyroid function studies
Same as the full description in the CMS dataset.
Parent Code
R94
Abnormal results of function studies

Code Classification

ChapterR00–R99Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
SectionR90-R94Abnormal findings on diagnostic imaging and in function studies, without diagnosis
CategoryR94Abnormal results of function studies
This CodeR94.6Abnormal results of thyroid function studies

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormal thyroid function test caused by substance
  • Abnormal thyroid function test due to assay interference
  • Abnormal thyroid hormone
  • Euthyroid
  • Finding of thyroid function
  • Radioactive iodine uptake above reference range
  • Serum thyroid stimulating hormone above reference range
  • Serum thyroid stimulating hormone below reference range
  • Serum thyroid stimulating hormone level outside reference range
  • Thyroid function tests abnormal
  • Thyroid hormone tests outside reference range
  • Thyroid stimulating hormone level above reference range
  • Thyroid stimulating hormone level below reference range

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Abnormal, abnormality, abnormalities
      • function studies
        • thyroid
    • Abnormal, abnormality, abnormalities
      • scan
        • thyroid
    • Findings, abnormal, inconclusive, without diagnosis
      • function study NEC
        • endocrine NEC
          • thyroid
    • Findings, abnormal, inconclusive, without diagnosis
      • scan NEC
        • thyroid
    • Findings, abnormal, inconclusive, without diagnosis
      • thyroid (function) (metabolic rate) (scan) (uptake)

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR SYM017
Abnormal findings without diagnosis
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Thyroid Diseases

Your thyroid is a small, butterfly-shaped gland in the front of your neck. It makes hormones that control the way the body uses energy. These hormones affect nearly every organ in your body and control many of your body's most important functions. For example, they affect your breathing, heart rate, weight, digestion, and moods.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert R94.6 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
794.5 Abn thyroid funct study
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About R94.6Overview

Is R94.6 (Abnormal results of function studies) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report abnormal results of thyroid function studies on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does R94.6 group to?

When abnormal results of thyroid function studies is the principal diagnosis on an inpatient stay, it groups to MS-DRG 643, 644, 645, with relative weights from 0.7683 to 1.6461 depending on complications. Higher weights mean higher Medicare reimbursement.

Can R94.6 be a principal diagnosis?

Use it with care. This is a symptom code, so once a definitive diagnosis explaining the abnormal results of thyroid function studies is established, that condition takes the principal position instead.

What is the ICD-9 equivalent of R94.6?

Under the General Equivalence Mappings, abnormal results of thyroid function studies converts to ICD-9-CM 794.5 (abn thyroid funct study). The mapping is a direct match.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.