M1A.18X0
Lead-induced chronic gout, vertebrae, without tophus (tophi)
M1A.18X0 (also written M1A18X0) is a billable ICD-10-CM diagnosis code for lead-induced chronic gout, vertebrae, without tophus (tophi). It is part of the FY2027 code set, effective October 1, 2026. It is one of the 242 codes in category M1A (Chronic gout). The Alphabetic Index lists it under 1 entry. Its 7th character, 0, means without tophus (tophi). Its coding notes include a Code first instruction, a Use additional code instruction, 1 Excludes1 entry and 11 Excludes2 entries.
7th character
Category M1A requires a 7th character. M1A.18 has only 5 characters, so a placeholder X fills the 6th position.
Code first
If the underlying condition listed here is present and known, sequence it first.
Use additional code
Add the listed code as a secondary code, if known.
- code to identify:
- Autonomic neuropathy in diseases classified elsewhere (G99.0)
- Calculus of urinary tract in diseases classified elsewhere (N22)
- Cardiomyopathy in diseases classified elsewhere (I43)
- Disorders of external ear in diseases classified elsewhere (H61.1-, H62.8-)
- Disorders of iris and ciliary body in diseases classified elsewhere (H22)
- Glomerular disorders in diseases classified elsewhere (N08)
Excludes1
Not coded here. The listed conditions generally should not be reported together.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (10 notes)
- arthropathic psoriasis (L40.5-)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- compartment syndrome (traumatic) (T79.A-)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the Musculoskeletal Rehabilitation clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026IPF Primary
IPF MS-DRG adjustment. A principal diagnosis of this code groups to one of these MS-DRGs. Which one depends on other facts of the stay, so the factor is a range:
| MS-DRG | Description | Factor |
|---|---|---|
| 917 | Poisoning and toxic effects of drugs w MCC | 1.19 |
| 918 | Poisoning and toxic effects of drugs w/out MCC | 1.12 |
Notes
Also from chapter/block level (1 note)
- Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition
Alphabetic Index terms
Terms the official Alphabetic Index lists for M1A.18. This code adds the 7th character. 1 entry