Is T40.416A a billable ICD-10-CM code?

Yes. T40.416A is a billable, specific ICD-10-CM code and is valid for submission on a claim.

Where does T40.416A sit in the tabular list?

Injury, poisoning and certain other consequences of external causes (S00-T88), in the block Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances (T36-T50).

T40.416A

T40.416A — Underdosing of fentanyl or fentanyl analogs, initial encounter

Billable / specific codeICD-10-CM

T40.416A is a billable, specific ICD-10-CM code for underdosing of fentanyl or fentanyl analogs, initial encounter. It is valid for submission on a claim.

7th character "A" — initial encounter

The appropriate 7th character is to be added to each code from category T40

A: initial encounter
D: subsequent encounter
S: sequela

Excludes2 inherited from the categories above T40.416A

Also inherited, and the opposite of Excludes1: these conditions are not part of T40.416A, but a patient can have both, so you may code both.

Written on T40 — Poisoning by, adverse effect of and underdosing of narcotics and psychodysleptics [hallucinogens]

drug dependence and related mental and behavioral disorders due to psychoactive substance use (F10.-F19.-)

Risk adjustment

T40.416A 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

T40.416A has not changed since FY2024 — no addition, revision or deletion across the FY2024–FY2027 ICD-10-CM releases.

Related codes at this level

Codes that share T40.416. If T40.416A is not quite right, the correct code is usually one of these.

Questions about T40.416A

Is T40.416A a billable ICD-10-CM code?: Yes. T40.416A is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does T40.416A sit in the tabular list?: Injury, poisoning and certain other consequences of external causes (S00-T88), in the block Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances (T36-T50).