ICD-10-CM > S00-T88 > T36-T50 > T38 > T38.8 > T38.81 > T38.816 T38.816 Underdosing of anterior pituitary [adenohypophyseal] hormones Non-Billable/Non-Specific Codes T38.816A..., initial encounterT38.816D..., subsequent encounterT38.816S..., sequela