MCMedicalCodingSoftware
R40.20

R40.20: Unspecified coma

Billable / specific codeICD-10-CM

R40.20 is a billable, specific ICD-10-CM code for unspecified coma. It is valid for submission on a claim.

Check R40.20 with the rest of the claim: free scrubber

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • Coma NOS
  • Unconsciousness NOS

Excludes1 inherited from the categories above R40.20

A category’s note binds every code beneath it.

Written on R40: Somnolence, stupor and coma

  • neonatal coma (P91.5)
  • somnolence, stupor and coma in diabetes (E08-E13)
  • somnolence, stupor and coma in hepatic failure (K72.-)
  • somnolence, stupor and coma in hypoglycemia (nondiabetic) (E15)

Other codes that can never be billed with R40.20

Their own Excludes1 notes name this code, so the conflict is not listed above.

  • R41.82Altered mental status, unspecified

Risk adjustment

R40.20 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:

  • HCC 202 Coma, Brain Compression/Anoxic Damage0.543 RAF

Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score. Look up the whole chart to see which of its HCCs the hierarchy would zero.

Medicare coverage

R40.20 is named in 14 Medicare coverage policies: 14 listing it as supporting medical necessity. Which one applies depends on your Medicare contractor.

  • A54799Billing and Coding: Urine Drug Testing
  • A55001Billing and Coding: Urine Drug Testing
  • A56612Billing and Coding: CT of the Head
  • A56771Billing and Coding: Special Electroencephalography

Alphabetic index entries that lead here

  • Coma

Code history

Unchanged in every release from FY2024 to FY2027.

Other codes under R40.2

ICD-10-CMFY2027· effective October 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release: see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.