Is S42.399 a billable ICD-10-CM code?

No. S42.399 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does S42.399 sit in the tabular list?

Injury, poisoning and certain other consequences of external causes (S00-T88), in the block Injuries to the shoulder and upper arm (S40-S49).

What cannot be coded together with S42.399?

S42.399 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 S42.399 (S42) and apply to it just the same.

S42.399

S42.399 — Other fracture of shaft of unspecified humerus

Non-billable headerICD-10-CM

S42.399 is a non-billable header ICD-10-CM code for other fracture of shaft of unspecified humerus. 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 all codes from category S42

A: initial encounter for closed fracture
B: initial encounter for open fracture
D: subsequent encounter for fracture with routine healing
G: subsequent encounter for fracture with delayed healing
K: subsequent encounter for fracture with nonunion
P: subsequent encounter for fracture with malunion
S: sequela

Excludes1 inherited from the categories above S42.399

These are not written on S42.399, but they bind it: a note on a category applies to every code beneath it. Billing S42.399 with anything listed here is a denial.

Written on S42 — Fracture of shoulder and upper arm

traumatic amputation of shoulder and upper arm (S48.-)

Excludes2 inherited from the categories above S42.399

Also inherited, and the opposite of Excludes1: these conditions are not part of S42.399, but a patient can have both, so you may code both.

Written on S42.3 — Fracture of shaft of humerus

physeal fractures of upper end of humerus (S49.0-)
physeal fractures of lower end of humerus (S49.1-)

Written on S42 — Fracture of shoulder and upper arm

periprosthetic fracture around internal prosthetic shoulder joint (M97.3)

Other codes that can never be billed with S42.399

These codes carry an Excludes1 note pointing at S42.399. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading S42.399 alone.

M84.3Stress fracture
M84.4Pathological fracture, not elsewhere classified

Risk adjustment

S42.399 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 history

S42.399 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 S42.399

7 child codes. Green means billable.

Related codes at this level

Codes that share S42.39. If S42.399 is not quite right, the correct code is usually one of these.

Questions about S42.399

Is S42.399 a billable ICD-10-CM code?: No. S42.399 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does S42.399 sit in the tabular list?: Injury, poisoning and certain other consequences of external causes (S00-T88), in the block Injuries to the shoulder and upper arm (S40-S49).
What cannot be coded together with S42.399?: S42.399 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 S42.399 (S42) and apply to it just the same.