T88.7XXAUnspecified adverse effect of drug or medicament, initial encounter

T88.7XXA is the ICD-10-CM diagnosis code for unspecified adverse effect of drug or medicament, initial encounter. It belongs to category T88 (other complications of surgical and medical care, not elsewhere classified), block T80-T88 (complications of surgical and medical care, not elsewhere classified) and chapter 19 (injury, poisoning and certain other consequences of external causes). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

The 7th character "A" means initial encounter: use it while the patient is receiving active treatment for the condition.

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 919 (Complications of Treatment with MCC, relative weight 1.763), DRG 920 (Complications of Treatment with CC, relative weight 0.9975) and DRG 921 (Complications of Treatment without CC/MCC, relative weight 0.6722), in MDC 21 (Injuries, Poisonings and Toxic Effects of Drugs), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 999.9 (other and unspecified complications of medical care, not elsewhere classified).