ICD-10-CM > S00-T88 > T36-T50 > T47 > T47.8 > T47.8X > T47.8X6 T47.8X6 Underdosing of other agents primarily affecting gastrointestinal system Non-Billable/Non-Specific Codes T47.8X6A..., initial encounterT47.8X6D..., subsequent encounterT47.8X6S..., sequela