ICD-10-CM > S00-T88 > T36-T50 > T36 > T36.0 > T36.0X > T36.0X6 T36.0X6 Underdosing of penicillins Non-Billable/Non-Specific Codes T36.0X6A..., initial encounterT36.0X6D..., subsequent encounterT36.0X6S..., sequela