Using accurate ICD-10 codes in rheumatology is essential to determine medical necessity, receive payment, and minimize audit risks. Lack of specific ICD-10 coding may lead to denial of claims, while accurate coding supports all types of services including referral, biologic infusion, imaging studies and treatments.
All ICD-10 codes represent the patient’s disease, regardless of the type of visit. Therefore, the diagnosis will always drive the same code, even if it is an initial consultation or follow up visit.
ICD-10 Coding in Rheumatology
ICD-10 coding in rheumatology exactly reflects the patient’s documented diagnosis. The diagnosis must include disease subtype, joint involvement, affected side, and relevant laboratory or imaging findings. ICD Codes for Rheumatology range from four to seven characters, with each additional character adding clinical detail such as which joint is affected, whether the disease is seropositive or seronegative, whether the condition is acute or chronic, and whether systemic or organ involvement is present.
A medical coder can only assign a code as specific as the documentation allows. Omitting details like laterality, joint location, disease activity, or lab confirmation forces the use of unspecified codes. Then, it can increase the risk of claim denials, payer audits, and delayed care. Providing accurate and detailed documentation ensures that ICD-10 codes used for Rheumatology convey the full clinical picture, supporting medical necessity for treatments.
Common ICD-10 Codes Used in Rheumatology
Here are some tables that list the most frequently used ICD-10 codes in rheumatology, covering inflammatory, autoimmune, degenerative, crystal-related, vasculitis, and symptom-based conditions.
➜ Rheumatoid Arthritis and Inflammatory Polyarthropathy
These ICD 10 codes cover the most common forms of rheumatoid arthritis, including seropositive and seronegative types.
| ICD-10 Code | Used for |
| M05.9 | RA with rheumatoid factor, unspecified |
| M05.79 | RA with rheumatoid factor, multiple sites, without organ or systems involvement |
| M06.9 | Rheumatoid arthritis, unspecified |
| M06.4 | Inflammatory polyarthropathy, unspecified |
| M08.00 | Juvenile RA, unspecified site |
| M08.20 | Systemic-onset JIA, unspecified site |
| M08.3 | Juvenile RA polyarthritis, seronegative |
| M08.40 | Pauciarticular JIA, unspecified |
| M45.9 | Ankylosing spondylitis, unspecified |
Healthcare providers should use M05 codes when rheumatoid arthritis is documented as rheumatoid factor (RF) positive or seropositive. M06 codes should be assigned when RA is documented as seronegative or without rheumatoid factor.
➜ Connective Tissue and Systemic Autoimmune Disorders
The table includes ICD-10 codes for systemic lupus erythematosus, Sjogren’s syndrome, systemic sclerosis, mixed connective tissue disease, and inflammatory myopathies. Each ICD-10 code is listed with specific conditions reflecting organ involvement or disease subtype.
Systemic Lupus Erythematosus
| ICD-10 Code | Used for |
| M32.9 | SLE, unspecified |
| M32.10 | SLE with organ involvement, unspecified |
| M32.11 | Endocarditis in SLE |
| M32.12 | Pericarditis in SLE |
| M32.13 | Lung involvement in SLE |
| M32.14 | Glomerular disease in SLE (lupus nephritis) |
| M32.15 | Tubulo-interstitial nephropathy in SLE |
| M32.19 | Other organ involvement in SLE |
Sjogren’s Syndrome
| ICD-10 Code | Used for |
| M35.00 | Sjogren syndrome, unspecified |
| M35.01 | Sjogren with keratoconjunctivitis |
| M35.02 | Sjogren with lung involvement |
| M35.03 | Sjogren with myopathy |
| M35.04 | Sjogren with tubulo-interstitial nephropathy |
| M35.09 | Sjogren with other organ involvement |
Systemic Sclerosis (Scleroderma)
| ICD-10 Code | Used for |
| M34.0 | Progressive systemic sclerosis |
| M34.1 | CREST syndrome |
| M34.2 | Drug/chemical-induced systemic sclerosis |
| M34.81 | Systemic sclerosis with lung involvement |
| M34.82 | Systemic sclerosis with myopathy |
| M34.83 | Systemic sclerosis with polyneuropathy |
| M34.9 | Systemic sclerosis, unspecified |
➜ Mixed Connective Tissue Disease and Inflammatory Myopathies
| ICD-10 Code | Used for |
| M35.1 | Mixed connective tissue disease (MCTD) |
| M33.00 | Juvenile dermatomyositis, unspecified |
| M33.02 | Juvenile dermatomyositis with myopathy |
| M33.10 | Dermatomyositis (adult), unspecified |
| M33.11 | Dermatomyositis with respiratory involvement |
| M33.12 | Dermatomyositis with myopathy |
| M33.20 | Polymyositis, unspecified |
| M33.21 | Polymyositis with respiratory involvement |
| M33.22 | Polymyositis with myopathy |
M35.1 is specific to MCTD and should not be used interchangeably with M35.9 (undifferentiated connective tissue disease). For inflammatory myopathies, providers should always document whether respiratory involvement or clinical myopathy is present to move beyond the unspecified code.
➜ Inflammatory Arthritis Beyond RA
The table lists ICD codes for psoriatic, reactive, and enteropathic arthritis, including joint-specific and subtype-specific codes.
Psoriatic Arthritis
| ICD-10 Code | Used for |
| L40.50 | Arthropathic psoriasis, unspecified |
| L40.51 | Distal interphalangeal psoriatic arthropathy |
| L40.52 | Psoriatic arthritis mutilans |
| L40.53 | Psoriatic spondylitis |
| L40.54 | Psoriatic juvenile arthropathy |
| L40.59 | Other psoriatic arthropathy |
Reactive Arthritis
| ICD-10 Code | Used for |
| M02.10 | Postdysenteric arthropathy, unspecified |
| M02.30 | Reiter’s disease, unspecified |
| M02.9 | Reactive arthropathy, unspecified |
Enteropathic Arthritis
| ICD-10 Code | Used for |
| M07.60 | Enteropathic arthropathy, unspecified |
| M07.661 | Enteropathic arthropathy, right knee |
| M07.69 | Enteropathic arthropathy, multiple sites |
Healthcare providers must code the underlying IBD (K50.x or K51.x) alongside M07.6x.
➜ Osteoarthritis and Degenerative Joint Disorders
This section includes knee, hip, and spinal osteoarthritis, as well as spondylosis ICD 10 codes.
Knee and Hip OA
| ICD-10 Code | Used for |
| M17.0 | Bilateral primary OA, knee |
| M17.11 | Primary OA, right knee |
| M17.12 | Primary OA, left knee |
| M17.31 | Secondary OA, right knee |
| M16.0 | Bilateral primary OA, hip |
| M16.11 | Primary OA, right hip |
| M16.12 | Primary OA, left hip |
| M19.90 | OA, unspecified site |
- Primary OA happens naturally with age (degenerative).
- Secondary OA happens because of another condition, like an injury, birth defect, or inflammatory disease.
- Use M17.3x (knee) or M16.4–6x (hip) codes for secondary OA.
- Always note the side of the joint (left, right, or both). If the side is not documented, use unspecified codes like M19.90.
- M19 codes are for OA in joints not specifically listed, or for multiple/unspecified sites.
Spinal OA and Spondylosis (M47.x)
| ICD-10 Code | Used for |
| M47.812 | Spondylosis without myelopathy, cervical |
| M47.814 | Spondylosis without myelopathy, thoracic |
| M47.816 | Spondylosis without myelopathy, lumbar |
| M47.817 | Spondylosis without myelopathy, lumbosacral |
| M47.819 | Spondylosis without myelopathy, unspecified |
Always specify the spinal region. When myelopathy or radiculopathy is present, use M47.1x or M47.2x accordingly.
➜ Crystal Arthropathies
The table below includes acute and chronic gout, CPPD, and other crystal arthropathies. Tophi presence and laterality are critical for coding.
Gout
| ICD-10 Code | Used for |
| M10.00 | Idiopathic gout, unspecified site |
| M10.061 | Idiopathic gout, right knee |
| M10.062 | Idiopathic gout, left knee |
| M10.9 | Gout, unspecified |
| M1A.9XX0 | Chronic gout, unspecified, without tophus |
| M1A.9XX1 | Chronic gout, unspecified, with tophus |
| M1A.0711 | Chronic gout, right ankle/foot, with tophus |
Use M10 for acute gout and M1A for chronic gout. The 7th character in M1A codes—indicating tophus presence (0 = without, 1 = with)—should always be documented.
CPPD and Other Crystal Arthropathies
| ICD-10 Code | Used for |
| M11.00 | Hydroxyapatite deposition disease, unspecified |
| M11.20 | Other chondrocalcinosis, unspecified |
| M11.9 | Crystal arthropathy, unspecified |
| M12.3 | Palindromic rheumatism |
➜ Vasculitis and Systemic Inflammatory Vascular Disorders
This section includes ICD codes for polyarteritis nodosa, GPA, Takayasu arteritis, and giant cell arteritis, with renal involvement and ANCA specificity when applicable.
| ICD-10 Code | Used for |
| M30.0 | Polyarteritis nodosa |
| M30.1 | Polyarteritis with lung involvement (Churg-Strauss/EGPA) |
| M31.30 | GPA (Wegener’s), without renal involvement |
| M31.31 | GPA (Wegener’s), with renal involvement |
| M31.4 | Takayasu arteritis |
| M31.5 | Giant cell arteritis with polymyalgia rheumatica |
| M31.6 | Other giant cell arteritis |
| M31.7 | Microscopic polyangiitis |
| I77.6 | Arteritis, unspecified (last resort only) |
Granulomatosis with polyangiitis (GPA) is coded as M31.31 when kidney involvement, such as glomerulonephritis, is documented. If kidney involvement is not present, M31.30 should be used.
Takayasu arteritis (M31.4) is a distinct condition and should not be grouped with giant cell arteritis, even though these two conditions may have overlapping clinical features.
The specific ANCA antibody type should be documented to support accurate diagnosis i.e.
- PR3-ANCA is more commonly associated with GPA.
- MPO-ANCA is more commonly linked with microscopic polyangiitis (M31.7)
➜ Symptom-Based Codes for Unconfirmed Diagnoses
These ICD 10 codes are used during initial evaluation when the diagnosis is not yet confirmed. They cover joint pain, effusion, fatigue, myalgia, and abnormal immunological findings.
| ICD-10 Code | Used for |
| M25.50 | Pain, unspecified joint |
| M25.561 | Pain, right knee |
| M25.562 | Pain, left knee |
| M25.40 | Effusion of joint |
| R76.8 | Abnormal immunological findings |
| R53.83 | Other fatigue |
| M79.1 | Myalgia |
Are There ICD Codes for a Rheumatology Consult?
There exists no separate ICD Code (ICD-10-CM) for a Rheumatology Consult. As an alternative, you can use ICD-10-CM Diagnosis/Symptom/Abnormal Finding codes which most closely represent why the patient was consulted; then, you will bill the E/M Service based on the type of Encounter.
When billing for a rheumatology consult, you need to use the ICD-10-CM code that best describes the reason the patient was referred to see the physician. It could be a diagnosed rheumatologic condition, i.e., rheumatoid arthritis or lupus, or it could be a symptom-based code, e.g., joint pain, if a definitive diagnosis has not been made. The official guidelines allow the reporting of signs, symptoms, abnormal test findings when a definitive diagnosis has not been established; and coding should be done to the highest level of specificity supported by documentation.
Some Common ICD-10-CM Codes Used For Rheumatology Referral
The common codes used for Rheumatology referrals would include either a single code or combination of codes that are related to the documentation provided by the referring provider’s reasons for referral:
- M25.50 — Pain in Unspecified Joint
- R76.8 — Other Specified Abnormal Immunological Findings In Serum
- M79.7 — Fibromyalgia
- M05.9 — Rheumatoid Arthritis With Rheumatoid Factor, Unspecified
- M06.9 — Rheumatoid Arthritis, Unspecified
- M32.9 — Systemic Lupus Erythematosis, Unspecified
- M35.00 — Sjogrens Syndrome, Unspecified
- M35.3 — Polymyalgia Rheumatica
- M10.9 — Gout, Unspecified
Note: These are only some examples of codes that may be used to refer to Rheumatology. The code(s) selected should be based upon the provider’s documentation and the current version of the code book.
Documentation Requirements for Accurate Rheumatology ICD-10 Coding
As using accurate ICD 10 codes is important for right Rheumatology billing, similarly proper clinical documentation is also essential for healthcare providers to deny any unwanted results in the shape of claim denials and payment delay.
The clinical notes must include the following details:
1). Affected Side
Providers must clearly document whether the condition affects the right side, left side, or both sides (bilateral). For example, specify “right knee,” “left wrist,” or “bilateral metacarpophalangeal (MCP) joints.”
2). Specific Joint or Body Part
Identify each joint or body part involved. For example, knee, hip, shoulder, MCP, PIP, or ankle. Simply writing “joint pain” is insufficient; the exact joint must be named to support proper documentation.
3). Acute vs. Chronic
Document whether the condition is acute or chronic. This is especially important for gout (M10 = acute, M1A = chronic), tendinopathy, or flares of rheumatoid arthritis or psoriatic arthritis.
4). Disease Activity
Record the current disease activity, such as remission, low, moderate, or high activity. For example, “RA with moderate disease activity in bilateral wrists and knees”. It supports medical necessity for continued therapy.
5). Laboratory Confirmation
Include lab results that support the diagnosis. Common rheumatology labs include RF, anti-CCP, ANA, anti-dsDNA, ANCA, ESR, and CRP. For example, “RF positive, anti-CCP elevated” allows accurate coding of seropositive RA (M05.x) versus seronegative RA (M06.x).
6). Organ or System Involvement
Document organ or system involvement and link it to the underlying rheumatologic condition. For example, “SLE with lupus nephritis (M32.14), systemic sclerosis with interstitial lung disease (M34.81).” This is essential for subcategory ICD-10 codes.
7). Complications and Comorbidities
Document any complications or related conditions, such as secondary osteoporosis, medication side effects (e.g., corticosteroid-induced), cardiovascular involvement, or comorbid autoimmune disorders.
FAQs
Is there an ICD-10 code for Rheumatology Consult?
There is no specific ICD-10 code for a rheumatology consult. ICD-10 codes describe the patient’s diagnosis, not the visit type. Consultation or evaluation services are reported using CPT codes, while ICD-10 codes reflect the condition being evaluated (such as M05.79 for rheumatoid arthritis or M32.14 for lupus nephritis).
Do ICD-10 codes change between initial and follow-up visits?
No. ICD-10 codes remain the same as long as the diagnosis remains the same. Only the CPT (E/M) code changes based on visit complexity and documentation.
When to use Symptom Codes vs. Confirmed Diagnosis Codes?
Healthcare providers should not overlap the use of symptoms codes and confirmed diagnosis codes. Symptom codes are used during the initial evaluation process or until lab results confirm the diagnosis. Once a confirmed diagnosis is established, switch to the confirmed diagnosis code and do not switch back to symptom codes during follow up visits.
