ICD-10-CM > S00-T88 > T36-T50 > T40 > T40.0 > T40.0X > T40.0X6 T40.0X6 Underdosing of opium Non-Billable/Non-Specific Codes T40.0X6A..., initial encounterT40.0X6D..., subsequent encounterT40.0X6S..., sequela