ICD-10-CM > S00-T88 > T36-T50 > T38 > T38.1 > T38.1X > T38.1X4 T38.1X4 Poisoning by thyroid hormones and substitutes, undetermined Non-Billable/Non-Specific Codes T38.1X4A..., initial encounterT38.1X4D..., subsequent encounterT38.1X4S..., sequela