M1A.1611 (Lead-induced chronic gout, right knee, with tophus (tophi)) compared with M1A.1621 (Lead-induced chronic gout, left knee, with tophus (tophi)), from the official CMS tabular data. M1A.1611 and M1A.1621 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.1611 and M1A.1621 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.1611Lead-induced chronic gout, right knee, with tophus (tophi) | M1A.1621Lead-induced chronic gout, left knee, with tophus (tophi) | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | M00-M99 — Diseases of the musculoskeletal system and connective tissue | M00-M99 — Diseases of the musculoskeletal system and connective tissue |
| Definition | Lead-induced chronic gout, right knee, with tophus (tophi) is a billable ICD-10-CM diagnosis code (M1A.1611). | Lead-induced chronic gout, left knee, with tophus (tophi) is a billable ICD-10-CM diagnosis code (M1A.1621). |
| 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 | toxic effects of lead and its compounds (T56.0-) | toxic effects of lead and its compounds (T56.0-) |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources