ICDcodes.org
FY2027

M35.1 — Other overlap syndromes

BillableCC

Is M35.1 billable?

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

M35.1 at a glance

CodeM35.1
DescriptionOther overlap syndromes
BillableYes
Code setICD-10-CM FY2027
Valid for encountersOctober 1, 2026 – September 30, 2027

Which MS-DRGs does M35.1 group to?

M35.1 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, M35.1 is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.

How is M35.1 listed in the Alphabetic Index?

These are the routes through the Alphabetic Index that lead to M35.1. They show the wording a clinician may have documented, which often differs from the Tabular description.

  • Disease, diseased › mixed connective tissue
  • Syndrome › connective tissue › overlap NEC

Excludes1 — never code together

The conditions below can never be reported together with M35.1 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.

  • polyangiitis overlap syndrome (M30.8)

Inclusion terms

Alternative wording in documentation that is classified to M35.1.

  • Mixed connective tissue disease

Excludes1 — never code together — inherited from M30-M36

The conditions below can never be reported together with M35.1 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 M35.1 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 M35.1, but a patient may have both at the same time. When documentation supports it, M35.1 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 M35.1 existed?

M35.1 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.

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

Which codes are confused with M35.1?

ICD-10-CM declares these codes mutually exclusive with M35.1 — exactly one of each pair can be correct for a given encounter.

What other codes are in the M35 family? (9)