T40.99 ICD-10-CM Code: Poisoning by, adverse effect of and underdosing of other psychodysleptics [hallucinogens]
Billing Status: NO. This is a clinician non-billable / parent hierarchy grouping in the ICD-10-CM system.
Official Registry Overview & Definition
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for T40.99 in the official ICD-10-CM tabular list.
Includes
Conditions the official ICD-10-CM tabular list includes under this code.
- adverse effect of correct substance properly administered
- poisoning by overdose of substance
- poisoning by wrong substance given or taken in error
- underdosing by (inadvertently) (deliberately) taking less substance than prescribed or instructed
Excludes1 — Not Coded Here
Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
- toxic reaction to local anesthesia in pregnancy (O29.3-) Compare T40.99 vs O29.3 →
Excludes2 — Not Included Here
Conditions not covered by this code, but which may be reported alongside it when both are present.
- drug dependence and related mental and behavioral disorders due to psychoactive substance use (F10.-F19.-) Compare T40.99 vs F10 →
- abuse and dependence of psychoactive substances (F10-F19) Compare T40.99 vs F10 →
- abuse of non-dependence-producing substances (F55.-) Compare T40.99 vs F55 →
- immunodeficiency due to drugs (D84.821) Compare T40.99 vs D84.821 →
- drug reaction and poisoning affecting newborn (P00-P96) Compare T40.99 vs P00 →
- pathological drug intoxication (inebriation) (F10-F19) Compare T40.99 vs F10 →
Code First
Underlying conditions that must be sequenced before this code.
- Code first, for adverse effects, the nature of the adverse effect, such as:
- adverse effect NOS (T88.7)
- aspirin gastritis (K29.-)
- blood disorders (D56-D76)
- contact dermatitis (L23-L25)
- dermatitis due to substances taken internally (L27.-)
- nephropathy (N14.0-N14.2)
Use Additional Code
Supplementary codes the tabular list directs you to add.
- Use additional code(s) to specify:
- manifestations of poisoning
- underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9)
- underdosing of medication regimen (Z91.12-, Z91.13-)
Change history
No changes recorded for this code — unchanged since the FY2016 baseline of the change ledger.
Verify Before Coding
- Not billable as written — a more specific code is required: T40.991A, T40.991D, T40.991S, T40.992A, T40.992D.
- Requires a 7th character. "The appropriate 7th character is to be added to each code from category T40" Options: T40.991A, T40.991D, T40.991S, T40.992A, T40.992D, T40.992S
From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim.
Contextual Map
Every relationship of T40.99 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.
Hierarchy
- T40.9 — Poisoning by, adverse effect of and underdosing of other and unspecified psychodysleptics [hallucinogens] [Hierarchy]
Referenced by Excludes2 notes
- T43 — Poisoning by, adverse effect of and underdosing of psychotropic drugs, not elsewhere classified [Excludes2](via T40.9.-): “psychodysleptics [hallucinogens] (T40.7-T40.9-)”
Nearest codes (40)
- T40 — Poisoning by, adverse effect of and underdosing of narcotics and psychodysleptics [hallucinogens] [Sibling]
- T40.902 — Poisoning by unspecified psychodysleptics [hallucinogens], intentional self-harm [Sibling]
- T40.902A — Poisoning by unspecified psychodysleptics [hallucinogens], intentional self-harm, initial encounter [Sibling]
- T40.902D — Poisoning by unspecified psychodysleptics [hallucinogens], intentional self-harm, subsequent encounter [Sibling]
- T40.902S — Poisoning by unspecified psychodysleptics [hallucinogens], intentional self-harm, sequela [Sibling]
- T40.903 — Poisoning by unspecified psychodysleptics [hallucinogens], assault [Sibling]
- T40.903A — Poisoning by unspecified psychodysleptics [hallucinogens], assault, initial encounter [Sibling]
- T40.903D — Poisoning by unspecified psychodysleptics [hallucinogens], assault, subsequent encounter [Sibling]
- and 32 more
Referenced by Other Codes
Official ICD-10-CM tabular notes on other codes that name T40.99 or its code family.
1 Excludes2 notes: T43 (via T40.9.-).
Frequently Asked Questions (FAQ) & Clinical Guidance
Can T40.99 be billed directly?
No. T40.99 (Poisoning by, adverse effect of and underdosing of other psychodysleptics [hallucinogens]) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.
Does T40.99 require a 7th character?
Yes. The appropriate 7th character is to be added to each code from category T40.
Nearest Codes in This Family
Official ICD-10-CM classifications closest to T40.99 in its code family, with their registry titles.
- T40.905S — Adverse effect of unspecified psychodysleptics [hallucinogens], sequela
- T40.906 — Underdosing of unspecified psychodysleptics [hallucinogens]
- T40.906A — Underdosing of unspecified psychodysleptics [hallucinogens], initial encounter
- T40.906D — Underdosing of unspecified psychodysleptics [hallucinogens], subsequent encounter
- T40.906S — Underdosing of unspecified psychodysleptics [hallucinogens], sequela
- T40.991 — Poisoning by other psychodysleptics [hallucinogens], accidental (unintentional)
- T40.991A — Poisoning by other psychodysleptics [hallucinogens], accidental (unintentional), initial encounter
- T40.991D — Poisoning by other psychodysleptics [hallucinogens], accidental (unintentional), subsequent encounter
- T40.991S — Poisoning by other psychodysleptics [hallucinogens], accidental (unintentional), sequela
- T40.992 — Poisoning by other psychodysleptics [hallucinogens], intentional self-harm