ICD-10-CM > S00-T88 > T36-T50 > T36 > T36.1 > T36.1X > T36.1X6 T36.1X6 Underdosing of cephalosporins and other beta-lactam antibiotics Non-Billable/Non-Specific Codes T36.1X6A..., initial encounterT36.1X6D..., subsequent encounterT36.1X6S..., sequela