T42.6X6A vs T42.6X6D
T42.6X6A (Underdosing of other antiepileptic and sedative-hypnotic drugs, initial encounter) compared with T42.6X6D (Underdosing of other antiepileptic and sedative-hypnotic drugs, subsequent encounter), from the official CMS tabular data. T42.6X6A and T42.6X6D code the same injury at a different phase of treatment.
Can these codes be reported together?
Same injury, other encounter phase. T42.6X6A and T42.6X6D 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
| T42.6X6AUnderdosing of other antiepileptic and sedative-hypnotic drugs, initial encounter | T42.6X6DUnderdosing of other antiepileptic and sedative-hypnotic drugs, subsequent encounter | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | S00-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) |
| Definition | Underdosing of other antiepileptic and sedative-hypnotic drugs, initial encounter is a billable ICD-10-CM diagnosis code (T42.6X6A). | Underdosing of other antiepileptic and sedative-hypnotic drugs, subsequent encounter is a billable ICD-10-CM diagnosis code (T42.6X6D). |
| 7th character | The appropriate 7th character is to be added to each code from category T42 | The 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