ICDcodes.org
FY2027

M35.81 — Multisystem inflammatory syndrome

BillableCC

Is M35.81 billable?

Yes — M35.81 is billable for FY2027. M35.81 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. M35.81 may be submitted for encounters from October 1, 2026 through September 30, 2027.

M35.81 at a glance

CodeM35.81
DescriptionMultisystem inflammatory syndrome
BillableYes
Code setICD-10-CM FY2027
Valid for encountersOctober 1, 2026 – September 30, 2027

Which MS-DRGs does M35.81 group to?

M35.81 sits in MDC 08 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.

  • 545Connective Tissue Disorders with MCCmedical
  • 546Connective Tissue Disorders with CCmedical
  • 547Connective Tissue Disorders without CC/MCCmedical

As a secondary diagnosis, M35.81 is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.

How is M35.81 listed in the Alphabetic Index?

These are the routes through the Alphabetic Index that lead to M35.81. They show the wording a clinician may have documented, which often differs from the Tabular description.

  • MIS-A
  • MIS-C
  • Multisystem inflammatory syndrome (in adult) (in children)
  • Pediatric inflammatory multisystem syndrome
  • PIMS
  • Syndrome › multisystem inflammatory
  • Syndrome › pediatric inflammatory multisystem

Code first

The underlying condition below must be sequenced before M35.81. M35.81 describes a manifestation and cannot be the principal or first-listed diagnosis.

  • , if applicable, COVID-19 (U07.1)

Use additional code

Report an additional code alongside M35.81 to fully describe the condition. M35.81 is sequenced first.

  • 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

Two codes may be needed to describe the condition fully. Whether M35.81 is sequenced first depends on the reason for the encounter.

  • 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)

Inclusion terms

Alternative wording in documentation that is classified to M35.81.

  • MIS-A
  • MIS-C
  • Multisystem inflammatory syndrome in adults
  • Multisystem inflammatory syndrome in children
  • Pediatric inflammatory multisystem syndrome
  • PIMS

Excludes1 — never code together — inherited from M30-M36

The conditions below can never be reported together with M35.81 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.

  • autoimmune disease, single organ or single cell-type -code to relevant condition category

Excludes1 — never code together — inherited from M35

The conditions below can never be reported together with M35.81 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.

  • reactive perforating collagenosis (L87.1)

Excludes2 — not included here — inherited from Chapter 13

The conditions below are not part of M35.81, but a patient may have both at the same time. When documentation supports it, M35.81 and the excluded code may both be reported.

  • arthropathic psoriasis (L40.5-)
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • compartment syndrome (traumatic) (T79.A-)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

How long has M35.81 existed?

M35.81 first appears in FY2021 (FY2020 is not available, so it may have appeared then).

Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.

What other codes are in the M35.8 family? (1)