M1A.4521 (Other secondary chronic gout, left hip, with tophus (tophi)) compared with M1A.4591 (Other secondary chronic gout, unspecified hip, with tophus (tophi)), from the official CMS tabular data. M1A.4521 and M1A.4591 code the same condition on opposite sides.
Same condition; these differ only in which side is documented.
These codes share a category and title and differ only in the side affected. The documentation decides which applies, and a bilateral code is reported only where the code set provides one.
Source: ICD-10-CM tabular list (laterality variant derived from the code title)
Same condition, opposite side. M1A.4521 and M1A.4591 name the same condition on opposite sides of the body.
Same category and title, differing only in which side is affected — the documentation decides which one applies, and a bilateral code is reported only where the code set provides one.
| M1A.4521Other secondary chronic gout, left hip, with tophus (tophi) | M1A.4591Other secondary chronic gout, unspecified hip, with tophus (tophi) | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99) | M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99) |
| Definition | Other secondary chronic gout, left hip, with tophus (tophi) is a billable ICD-10-CM diagnosis code (M1A.4521). | Other secondary chronic gout, unspecified hip, with tophus (tophi) is a billable ICD-10-CM diagnosis code (M1A.4591). |
| 7th character | The appropriate 7th character is to be added to each code from category M1A | The appropriate 7th character is to be added to each code from category M1A |
| Use additional code | code to identify: Autonomic neuropathy in diseases classified elsewhere (G99.0) Calculus of urinary tract in diseases classified elsewhere (N22) | code to identify: Autonomic neuropathy in diseases classified elsewhere (G99.0) Calculus of urinary tract in diseases classified elsewhere (N22) |
| Code first | associated condition | associated condition |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources