2026 ICD-10-CM Diagnosis Code G93.31Postviral fatigue syndrome

ICD-10-CM Codes›G00–G99›G89-G99›G93

ICD-10-CM G93.31
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G93.31 is a billable ICD-10-CM diagnosis code for postviral fatigue syndrome. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 947 through 948. Coders also document this condition as postviral excessive daytime sleepiness. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other nervous system disorders (neither hereditary nor degenerative).

Code Identity

ICD-10-CM Code
G93.31
Billable Status
Yes — Valid for Submission
Code Describes
Postviral fatigue syndrome
Short Description
Postviral fatigue syndrome
Same as the full description in the CMS dataset.
Parent Code
G93.3
Postviral and related fatigue syndromes

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG89-G99Other disorders of the nervous system
CategoryG93Other disorders of brain
This CodeG93.31Postviral fatigue syndrome

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Postviral excessive daytime sleepiness
  • Postviral fatigue syndrome
  • Postviral infection debility

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

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

CCSR NVS020
Other nervous system disorders (neither hereditary nor degenerative)
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Fatigue

Fatigue is a feeling of weariness, tiredness, or lack of energy. It can interfere with your usual daily activities. Fatigue can be a normal response to physical activity, emotional stress, boredom, or lack of sleep. But sometimes it can be a sign of a mental or physical condition.

The full article covers:

  • What is fatigue?
  • What causes fatigue?
  • What can I do to manage fatigue?

Read the full article at MedlinePlus

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

Code History & ChangesHistory

Replacement G93.31 replaces the following previously assigned code(s):

  • G93.3 - Postviral and related fatigue syndromes
  • G93.3 - Postviral fatigue syndrome
FY 2023AddedAdded to the ICD-10-CM code setEffective October 1, 2022.
FY 2024–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About G93.31Overview

What is the ICD-10 code for postviral fatigue syndrome?

The ICD-10-CM code for postviral fatigue syndrome is G93.31 (sometimes written as G9331). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is G93.31 (Postviral and related fatigue syndromes) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report postviral fatigue syndrome on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does G93.31 group to?

When postviral fatigue syndrome is the principal diagnosis on an inpatient stay, it groups to MS-DRG 947, 948, with relative weights from 0.8005 to 1.2694 depending on complications. Higher weights mean higher Medicare reimbursement.