Is W56.31 a billable ICD-10-CM code?

No. W56.31 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does W56.31 sit in the tabular list?

External causes of morbidity (V00-Y99), in the block Exposure to animate mechanical forces (W50-W64).

What cannot be coded together with W56.31?

W56.31 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 W56.31 (W56) and apply to it just the same.

W56.31

W56.31 — Bitten by other marine mammals

Non-billable headerICD-10-CM

W56.31 is a non-billable header ICD-10-CM code for bitten by other marine mammals. 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 W56

A: initial encounter
D: subsequent encounter
S: sequela

Excludes1 inherited from the categories above W56.31

These are not written on W56.31, but they bind it: a note on a category applies to every code beneath it. Billing W56.31 with anything listed here is a denial.

Written on W56 — Contact with nonvenomous marine animal

contact with venomous marine animal (T63.-)

Other codes that can never be billed with W56.31

These codes carry an Excludes1 note pointing at W56.31. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading W56.31 alone.

W55Contact with other mammals

Risk adjustment

W56.31 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 W56.31 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 W56.31.

Bite, bitten by›mammal NEC›marine
Contact›with›mammal›marine›specified NEC›bite

Code history

W56.31 has not changed since FY2024 — no addition, revision or deletion across the FY2024–FY2027 ICD-10-CM releases.

Code to one of these instead W56.31

3 child codes. Green means billable.

Related codes at this level

Codes that share W56.3. If W56.31 is not quite right, the correct code is usually one of these.

Questions about W56.31

Is W56.31 a billable ICD-10-CM code?: No. W56.31 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does W56.31 sit in the tabular list?: External causes of morbidity (V00-Y99), in the block Exposure to animate mechanical forces (W50-W64).
What cannot be coded together with W56.31?: W56.31 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 W56.31 (W56) and apply to it just the same.