M05.9
BillableRheumatoid arthritis with rheumatoid factor, unspecified
HCC Category Mapping
V28HCC 93 — Rheumatoid Arthritis and Inflammatory Connective Tissue Disease
0.175V24HCC 40 — Rheumatoid Arthritis and Inflammatory Connective Tissue Disease
0.307ESRDHCC 40 — Rheumatoid Arthritis and Inflammatory Connective Tissue Disease
0.000RxHCCHCC 83 — Rheumatoid Arthritis and Inflammatory Connective Tissue Disease
0.000What This Code Means
A type of rheumatoid arthritis where the patient tests positive for rheumatoid factor (an antibody in the blood), but the specific joints affected are not documented.
Coding Tips
- •Use this code only when rheumatoid factor is confirmed positive but site of arthritis is unspecified or generalized
- •If specific joint involvement is documented, use more specific M05 codes with anatomical site designations
Clinical Significance
This unspecified code for seropositive rheumatoid arthritis indicates confirmed autoimmune inflammatory arthritis with positive rheumatoid factor but without further specification of site or organ involvement. While it maps to an HCC, more specific codes should be pursued whenever possible to accurately reflect disease burden and support clinical decision-making.
Documentation Requirements
- ✓Clinical diagnosis of rheumatoid arthritis clearly documented by the treating provider
- ✓Rheumatoid factor lab result status (positive or negative) consistent with the code selected
- ✓Affected joint(s) specified with laterality (right, left, or bilateral)
- ✓Current disease status: active, in remission, or chronic stable
- ✓Current treatment plan including medications (disease-modifying antirheumatic drugs, biologics, nonsteroidal anti-inflammatory drugs)
- ✓Query provider for specific laterality or site to assign a more specific code when possible
- ✓Assessment and plan addressing rheumatoid arthritis at each encounter where it impacts care or treatment
Commonly Confused Codes
M06.9 (Rheumatoid arthritis, unspecified) — A nonspecific code that does not indicate rheumatoid factor status; avoid when rheumatoid factor status is knownM05.0x-M05.6x (Rheumatoid arthritis with organ involvement such as Felty syndrome, rheumatoid lung, vasculitis) — Use these when extra-articular manifestations are documentedM19.x (Osteoarthritis) — Osteoarthritis is a degenerative, non-autoimmune condition; do not confuse with rheumatoid arthritis which is inflammatory and autoimmune
Code Hierarchy
└M05Rheumatoid arthritis with rheumatoid factor└M05.9Rheumatoid arthritis with rheumatoid factor, unspecified
└M05.9Rheumatoid arthritis with rheumatoid factor, unspecified