Is A51.4 a billable ICD-10-CM code?

No. A51.4 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does A51.4 sit in the tabular list?

Certain infectious and parasitic diseases (A00-B99), in the block Infections with a predominantly sexual mode of transmission (A50-A64).

A51.4

A51.4 — Other secondary syphilis

Non-billable headerICD-10-CM

A51.4 is a non-billable header ICD-10-CM code for other secondary syphilis. It cannot be billed on its own: choose one of the more specific child codes below.

Other codes that can never be billed with A51.4

These codes carry an Excludes1 note pointing at A51.4. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading A51.4 alone.

M63Disorders of muscle in diseases classified elsewhere
M90Osteopathies in diseases classified elsewhere
H20.0Acute and subacute iridocyclitis
K77Liver disorders in diseases classified elsewhere

Risk adjustment

A51.4 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.

Code to one of these instead A51.4

7 child codes. Green means billable.

Related codes at this level

Codes that share A51. If A51.4 is not quite right, the correct code is usually one of these.

Questions about A51.4

Is A51.4 a billable ICD-10-CM code?: No. A51.4 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does A51.4 sit in the tabular list?: Certain infectious and parasitic diseases (A00-B99), in the block Infections with a predominantly sexual mode of transmission (A50-A64).