Is M1A.00 a billable ICD-10-CM code?

No. M1A.00 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does M1A.00 sit in the tabular list?

Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Inflammatory polyarthropathies (M05-M14).

What cannot be coded together with M1A.00?

M1A.00 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above M1A.00 (M1A) and apply to it just the same.

M1A.00

M1A.00 — Idiopathic chronic gout, unspecified site

Non-billable headerICD-10-CM

M1A.00 is a non-billable header ICD-10-CM code for idiopathic chronic gout, unspecified site. It cannot be billed on its own: choose one of the more specific child codes below. This code also requires a 7th character before it is complete.

This code requires a 7th character

The appropriate 7th character is to be added to each code from category M1A

0: without tophus (tophi)
1: with tophus (tophi)

Excludes1 inherited from the categories above M1A.00

These are not written on M1A.00, but they bind it: a note on a category applies to every code beneath it. Billing M1A.00 with anything listed here is a denial.

Written on M1A — Chronic gout

gout NOS (M10.-)

Excludes2 inherited from the categories above M1A.00

Also inherited, and the opposite of Excludes1: these conditions are not part of M1A.00, but a patient can have both, so you may code both.

Written on M1A — Chronic gout

acute gout (M10.-)

Other codes that can never be billed with M1A.00

These codes carry an Excludes1 note pointing at M1A.00. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading M1A.00 alone.

E72Other disorders of amino-acid metabolism
E79Disorders of purine and pyrimidine metabolism

Risk adjustment

M1A.00 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

How M1A.00 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to M1A.00.

Gout, chronic›idiopathic

Code history

M1A.00 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Code to one of these instead M1A.00

2 child codes. Green means billable.

Related codes at this level

Codes that share M1A.0. If M1A.00 is not quite right, the correct code is usually one of these.

Questions about M1A.00

Is M1A.00 a billable ICD-10-CM code?: No. M1A.00 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does M1A.00 sit in the tabular list?: Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Inflammatory polyarthropathies (M05-M14).
What cannot be coded together with M1A.00?: M1A.00 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above M1A.00 (M1A) and apply to it just the same.