ICD-10-CM Code First Notes · Chapter 13 · FY 2027 M00-M99

Code First Notes in Chapter 13: Diseases of the musculoskeletal system and connective tissue ICD-10-CM

A Code First note means the underlying condition named in the note is sequenced before this code. In Chapter 13 (M00-M99), notes printed in the chapter name other codes 87 times, and Code First Notes anywhere in the Tabular List name the chapter’s codes 53 times, covering 30 distinct codes, categories and ranges. Switch views to read the list either way.

✓ From the official FY 2027 ICD-10-CM Tabular ListDefinitions follow the Official Guidelines, Section I.A
87
References in Its Notes
53
References to Its Codes
30
Chapter Codes Named
M00-M99
Chapter 13
Chapter 13

Code First Notes by the code that carries the note

29 of 29 shown
  • M01 Direct infections of joint in infectious and parasitic diseases classified elsewhere applies to 24 codes
  • M02 Postinfective and reactive arthropathies applies to 121 codes
    • congenital syphilis [Clutton's joints] (A50.5)
    • enteritis due to Yersinia enterocolitica (A04.6)
    • infective endocarditis (I33.0)
    • viral hepatitis (B15-B19)
  • M05.A Abnormal rheumatoid factor and anti-citrullinated protein antibody with rheumatoid arthritis
    • rheumatoid arthritis with rheumatoid factor by site, if known (M05.00 to M05.8A)
  • M10.1 Lead-induced gout applies to 24 codes
    • toxic effects of lead and its compounds (T56.0-)
  • M14.8 Arthropathies in other specified diseases classified elsewhere applies to 24 codes
    • amyloidosis (E85.-)
    • erythema multiforme (L51.-)
    • erythema nodosum (L52)
    • hemochromatosis (E83.11-)
    • hyperparathyroidism (E21.-)
    • hypothyroidism (E00-E03)
    • sickle-cell disorders (D57.-)
    • thyrotoxicosis [hyperthyroidism] (E05.-)
    • Whipple's disease (K90.81)
  • M1A.1 Lead-induced chronic gout applies to 48 codes
    • toxic effects of lead and its compounds (T56.0-)
  • M31.11 Hematopoietic stem cell transplantation-associated thrombotic microangiopathy [HSCT-TMA]
    • complications of bone marrow transplant (T86.0-)
    • complications of stem cell transplant (T86.5)
  • M34.2 Systemic sclerosis induced by drug and chemical
    • poisoning due to drug or toxin, if applicable (T36-T65 with fifth or sixth character 1-4)
  • M35.81 Multisystem inflammatory syndrome
    • , if applicable, COVID-19 (U07.1)
  • M36.0 Dermato(poly)myositis in neoplastic disease
  • M36.1 Arthropathy in neoplastic disease
  • M36.2 Hemophilic arthropathy
    • factor VIII deficiency (D66)
    • with vascular defect (D68.0-)
    • factor IX deficiency (D67)
    • hemophilia (classical) (D66)
    • hemophilia B (D67)
    • hemophilia C (D68.1)
  • M36.3 Arthropathy in other blood disorders
    • disease of blood and blood-forming organs, unspecified (D75.9)
    • other hemoglobinopathies (D58.2)
    • thalassemia (D56.-)
  • M36.4 Arthropathy in hypersensitivity reactions classified elsewhere
    • Henoch (-Schönlein) purpura (D69.0)
    • serum sickness (T80.6-)
  • M36.8 Systemic disorders of connective tissue in other diseases classified elsewhere
  • M49 Spondylopathies in diseases classified elsewhere applies to 10 codes
    • brucellosis (A23.-)
    • Charcot-Marie-Tooth disease (G60.0)
    • enterobacterial infections (A01-A04)
    • osteitis fibrosa cystica (E21.0)
  • M51.A0 Intervertebral annulus fibrosus defect, lumbar region, unspecified size
  • M51.A1 Intervertebral annulus fibrosus defect, small, lumbar region
  • M51.A2 Intervertebral annulus fibrosus defect, large, lumbar region
  • M51.A3 Intervertebral annulus fibrosus defect, lumbosacral region, unspecified size
    • , if applicable, lumbosacral disc herniation (M51.17, M51.27)
  • M51.A4 Intervertebral annulus fibrosus defect, small, lumbosacral region
    • , if applicable, lumbosacral disc herniation (M51.17, M51.27)
  • M51.A5 Intervertebral annulus fibrosus defect, large, lumbosacral region
    • , if applicable, lumbosacral disc herniation (M51.17, M51.27)
  • M62.84 Sarcopenia
    • disorders of myoneural junction and muscle disease in diseases classified elsewhere (G73.-)
    • other and unspecified myopathies (G72.-)
    • primary disorders of muscles (G71.-)
  • M63 Disorders of muscle in diseases classified elsewhere applies to 24 codes
  • M89.7 Major osseous defect applies to 24 codes
  • M90.5 Osteonecrosis in diseases classified elsewhere applies to 24 codes
  • M90.6 Osteitis deformans in neoplastic diseases applies to 24 codes
  • M90.8 Osteopathy in diseases classified elsewhere applies to 24 codes
  • M94.3 Chondrolysis applies to 3 codes
    • any associated slipped upper femoral epiphysis (nontraumatic) (M93.0-)

The first view lists notes printed in this chapter (a note on a category or block applies to every code beneath it). The second lists codes of this chapter named by Code First Notes anywhere in the Tabular List, including notes in other chapters.

Questions About Code First Notes

What does a Code First note mean?

A Code First note means the underlying condition named in the note is sequenced before the code that carries the note. Under the etiology/manifestation convention, a “code first” note appears at the manifestation code and a “use additional code” note at the etiology code (Section I.A.13). The FY 2027 Tabular List has 810 of them; 600 name other codes, with 736 references to 429 distinct codes, categories and ranges.

Can a code with a Code First note be the principal diagnosis?

Not when it is a manifestation code. Codes titled “in diseases classified elsewhere” are never permitted as the first-listed or principal diagnosis; they must follow the underlying condition. The etiology and manifestation page lists them all.

Related References

ICD-10-CM Official GuidelinesICD-10-CM Code LookupICD-10-CM Codes ListCode Lists by Tag

Source: FY 2027 ICD-10-CM Tabular List (CMS and NCHS) and the ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, Section I.A. ICD List is not affiliated with CMS or NCHS.