ICD10BillableValid for clinical use

ICD-10 Code M35.81: Multisystem inflammatory syndrome

M35.81 is a billable ICD-10 diagnosis code used to classify Multisystem inflammatory syndrome in medical records and claims. You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records. ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Diseases of the musculoskeletal system and connective tissue (M00-M99).

Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026

What is this code?

ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Diseases of the musculoskeletal system and connective tissue (M00-M99).

When is it used?

  • May be used when a clinician documents multisystem inflammatory syndrome in a patient's medical record.
  • May appear in hospital records, claims, referrals, and clinical documentation.
  • This code can be used as a clinically usable diagnosis entry in standardized coding workflows.

What it does not mean

  • A code alone does not explain severity, treatment plan, or outcome.
  • A medical code should not be treated as a substitute for a doctor's diagnosis or advice.

Code hierarchy

chapter
13Diseases of the musculoskeletal system and connective tissue (M00-M99)
block
M30-M36Systemic connective tissue disorders
category
M35Other systemic involvement of connective tissue
category
M35.8Other specified systemic involvement of connective tissue
currentM35.8

Official coding notes

Inclusion terms
  • MIS-A
  • MIS-C
  • Multisystem inflammatory syndrome in adults
  • Multisystem inflammatory syndrome in children
  • Pediatric inflammatory multisystem syndrome
  • PIMS
Applicable to
  • code, if applicable, for:
  • exposure to COVID-19 or SARS-CoV-2 infection (Z20.822)
  • personal history of COVID-19 (Z86.16)
  • post COVID-19 condition (U09.9)
  • , if applicable, COVID-19 (U07.1)
Code first
  • , if applicable, COVID-19 (U07.1)
Use additional code
  • code, if applicable, for:
  • exposure to COVID-19 or SARS-CoV-2 infection (Z20.822)
  • personal history of COVID-19 (Z86.16)
  • post COVID-19 condition (U09.9)
Code also
  • any associated complications such as:
  • acute hepatic failure (K72.0-)
  • acute kidney failure (N17.-)
  • acute myocarditis (I40.-)
  • acute respiratory distress syndrome (J80)
  • cardiac arrhythmia (I47-I49.-)
  • pneumonia due to COVID-19 (J12.82)
  • severe sepsis (R65.2-)
  • viral cardiomyopathy (B33.24)
  • viral pericarditis (B33.23)

Where you may see this code

You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.

Related specialists

Orthopedic SpecialistRheumatologist

Coding guidelines

Common synonyms

Multisystem inflammatory syndrome

Frequently asked questions

Code details

CodeM35.81
SystemICD10
Display nameMultisystem inflammatory syndrome
ChapterDiseases of the musculoskeletal system and connective tissue (M00-M99)
BlockSystemic connective tissue disorders

Flags

BillableYes
Valid clinical useYes

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

Index terms

Matched terms
MIS-AMIS-CMultisystem inflammatory syndrome(in adult) (in children)PIMSPediatric inflammatory multisystem syndromeSyndromeSyndrome

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.

ICD-10 Code M35.81 for Multisystem inflammatory syndrome | HealthAssure