MCMCB Pro
M00.9

M00.9Pyogenic arthritis, unspecified

Billable / specific codeICD-10-CM

M00.9 is a billable, specific ICD-10-CM code for pyogenic arthritis, unspecified. It is valid for submission on a claim.

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • Infective arthritis NOS

Risk adjustment

M00.9 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:

  • HCC 92 Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis0.479 RAF

Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.

Medicare coverage

M00.9 is named in 10 Medicare coverage policies 4 listing it as supporting medical necessity, and 6 listing it as NOT covered. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

  • A58865Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Woundnot covered
  • A58893Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Woundnot covered
  • A59374Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Woundnot covered
  • A59434Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Woundnot covered

How M00.9 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to M00.9.

  • Arthritis, arthriticpyogenic or pyemic(any site except spine)
  • Infection, infected, infectiveacromioclavicular
  • Infection, infected, infectivehip NEC(joint)
  • Infection, infected, infectivejoint NEC
  • Infection, infected, infectiveknee NEC(joint)
  • Infection, infected, infectivemetatarsophalangeal
  • Infection, infected, infectiveshoulder NEC(joint)
  • Abscesskneejoint
  • Disease, diseasedhipsuppurative
  • Infection, infected, infectiveknee NECjoint

Related codes at this level

Codes that share M00. If M00.9 is not quite right, the correct code is usually one of these.

Questions about M00.9

Is M00.9 a billable ICD-10-CM code?
Yes. M00.9 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does M00.9 sit in the tabular list?
Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Infectious arthropathies (M00-M02).
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.