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T42.8X4A vs T42.8X4D

T42.8X4A (Poisoning by antiparkinsonism drugs and other central muscle-tone depressants, undetermined, initial encounter) compared with T42.8X4D (Poisoning by antiparkinsonism drugs and other central muscle-tone depressants, undetermined, subsequent encounter), from the official CMS tabular data. T42.8X4A and T42.8X4D code the same injury at a different phase of treatment.

Can these codes be reported together?

Same injury, other encounter phase. T42.8X4A and T42.8X4D code the same injury at a different phase of treatment, set by the 7th character.

The 7th character records the type of care given at the encounter being coded (ICD-10-CM Official Guidelines, Section I.C.19.a), so one encounter takes one of these, not both.

Side by side

T42.8X4APoisoning by antiparkinsonism drugs and other central muscle-tone depressants, undetermined, initial encounterT42.8X4DPoisoning by antiparkinsonism drugs and other central muscle-tone depressants, undetermined, subsequent encounter
Billing statusBillableBillable
ClassificationS00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)
DefinitionPoisoning by antiparkinsonism drugs and other central muscle-tone depressants, undetermined, initial encounter is a billable ICD-10-CM diagnosis code (T42.8X4A).Poisoning by antiparkinsonism drugs and other central muscle-tone depressants, undetermined, subsequent encounter is a billable ICD-10-CM diagnosis code (T42.8X4D).
7th characterThe appropriate 7th character is to be added to each code from category T42The appropriate 7th character is to be added to each code from category T42
Includes
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
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
Use additional code
code(s) to specify:
manifestations of poisoning
underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9)
code(s) to specify:
manifestations of poisoning
underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9)
Code first
, for adverse effects, the nature of the adverse effect, such as:
adverse effect NOS (T88.7)
, for adverse effects, the nature of the adverse effect, such as:
adverse effect NOS (T88.7)

Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources