ICD-10-CM > S00-T88 > T36-T50 > T50 > T50.9 > T50.90 > T50.906 T50.906 Underdosing of unspecified drugs, medicaments and biological substances Non-Billable/Non-Specific Codes T50.906A..., initial encounterT50.906D..., subsequent encounterT50.906S..., sequela