T40.904A — Poisoning by unspecified psychodysleptics [hallucinogens], undetermined, initial encounter
T40.904A is a billable, specific ICD-10-CM code for poisoning by unspecified psychodysleptics [hallucinogens], undetermined, 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 T40.904A
Also inherited, and the opposite of Excludes1: these conditions are not part of T40.904A, but a patient can have both, so you may code both.
Risk adjustment
T40.904A risk-adjusts. Under the CMS-HCC V28 model it maps to this category:
- HCC 137 Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications0.424 RAF
Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score. Look up the whole chart to see which of its HCCs the hierarchy would zero.
Medicare coverage
T40.904A is named in 10 Medicare coverage policies — 10 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A54799Billing and Coding: Urine Drug Testing
- A55001Billing and Coding: Urine Drug Testing
- A56612Billing and Coding: CT of the Head
- A56645Billing and Coding: Controlled Substance Monitoring and Drugs of Abuse Testing
Code history
T40.904A 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 T40.904. If T40.904A is not quite right, the correct code is usually one of these.
Questions about T40.904A
- Is T40.904A a billable ICD-10-CM code?
- Yes. T40.904A is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does T40.904A 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).