2026 ICD-10-CM Diagnosis Code M13.0Polyarthritis, unspecified
ICD-10-CM Codes›M00–M99›M05-M14›M13
- Billable — Valid for Submission
- Chronic Condition
M13.0 is a billable ICD-10-CM diagnosis code for polyarthritis, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 553 through 554. Coders also document this condition as acute polyarthritis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified joint disorders.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acute polyarthritis
- Camptodactyly, arthropathy, coxa-vara, pericarditis syndrome
- Dilated cardiomyopathy due to polyarteritis nodosa
- Fixed flexion deformity finger
- Polyarthritis associated with another disorder
- Polyarthritis associated with hemochromatosis
- Polyarthropathy
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
- Polyarthritis, polyarthropathy - See Also: Arthritis; - M13.0
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- Polyarthritis, polyarthropathy
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Arthritis
acute or chronic inflammation of joints.Arthritis, Experimental
arthritis that is induced in experimental animals. immunological methods and infectious agents can be used to develop experimental arthritis models. these methods include injections of stimulators of the immune response, such as an adjuvant (adjuvants, immunologic) or collagen.Arthritis, Gouty
arthritis, especially of the great toe, as a result of gout. acute gouty arthritis often is precipitated by trauma, infection, surgery, etc. the initial attacks are usually monoarticular but later attacks are often polyarticular. acute and chronic gouty arthritis are associated with accumulation of monosodium urate in and around affected joints.Arthritis, Infectious
arthritis caused by bacteria; rickettsia; mycoplasma; viruses; fungi; or parasites.Arthritis, Juvenile
arthritis in children, with onset before 16 years of age. the terms juvenile rheumatoid arthritis (jra) and juvenile idiopathic arthritis (jia) refer to classification systems for chronic arthritis in children. only one subtype of juvenile arthritis (polyarticular-onset, rheumatoid factor-positive) clinically resembles adult rheumatoid arthritis and is considered its childhood equivalent.Arthritis, Psoriatic
a type of inflammatory arthritis associated with psoriasis, often involving the axial joints and the peripheral terminal interphalangeal joints. it is characterized by the presence of hla-b27-associated spondylarthropathy, and the absence of rheumatoid factor.Arthritis, Reactive
an aseptic, inflammatory arthritis developing secondary to a primary extra-articular infection, most typically of the gastrointestinal tract or urogenital system. the initiating trigger pathogens are usually shigella; salmonella; yersinia; campylobacter; or chlamydia trachomatis. reactive arthritis is strongly associated with hla-b27 antigen.Arthritis, Rheumatoid
a chronic systemic disease, primarily of the joints, marked by inflammatory changes in the synovial membranes and articular structures, widespread fibrinoid degeneration of the collagen fibers in mesenchymal tissues, and by atrophy and rarefaction of bony structures. etiology is unknown, but autoimmune mechanisms have been implicated.Arthritis-Encephalitis Virus, Caprine
a species of lentivirus, subgenus ovine-caprine lentiviruses (lentiviruses, ovine-caprine), closely related to visna-maedi virus and causing acute encephalomyelitis; chronic arthritis; pneumonia; mastitis; and glomerulonephritis in goats. it is transmitted mainly in the colostrum and milk.Crystal Arthropathies
joint disorders that are characterized by accumulation of microcrystals in and around the joint including in the synovial fluid. they are classified according to the chemical nature of the crystals such as calcium pyrophosphate; basic calcium phosphates; and monosodium urate (see uric acid).Lyme Disease
an infectious disease caused by a spirochete, borrelia burgdorferi, which is transmitted chiefly by ixodes dammini (see ixodes) and pacificus ticks in the united states and ixodes ricinis (see ixodes) in europe. it is a disease with early and late cutaneous manifestations plus involvement of the nervous system, heart, eye, and joints in variable combinations. the disease was formerly known as lyme arthritis and first discovered at old lyme, connecticut.Osteoarthritis
a progressive, degenerative joint disease, the most common form of arthritis, especially in older persons. the disease is thought to result not from the aging process but from biochemical changes and biomechanical stresses affecting articular cartilage. in the foreign literature it is often called osteoarthrosis deformans.Rheumatic Fever
a febrile disease occurring as a delayed sequela of infections with streptococcus pyogenes. it is characterized by multiple focal inflammatory lesions of the connective tissue structures, such as the heart, blood vessels, and joints (polyarthritis) and brain, and by the presence of aschoff bodies in the myocardium and skin.Spondylarthritis
inflammation of the joints of the spine, the intervertebral articulations.Joints
also known as articulations, these are points of connection between the ends of certain separate bones, or where the borders of other bones are juxtaposed.Spine
the spinal or vertebral column.
Patient EducationClinical
Arthritis
If you feel pain and stiffness in your body or have trouble moving around, you might have arthritis. Any disorder that affects the joints is often called arthritis. Joints are places where two bones meet, such as your elbow or knee.
The full article covers:
- What is arthritis?
- What are the types of arthritis?
- What are the symptoms of arthritis?
- Who is more likely to get arthritis?
- How is arthritis diagnosed?
- What are the treatments for arthritis?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert M13.0 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M13.0Overview
Is M13.0 (Other arthritis) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report polyarthritis, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does M13.0 group to?
When polyarthritis, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 553, 554, with relative weights from 0.8301 to 1.2963 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of M13.0?
Under the General Equivalence Mappings, polyarthritis, unspecified converts to ICD-9-CM 716.50 (polyarthritis NOS-unspec). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:
- The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
- The condition places limitations on self-care, independent living, and social interactions.
