ICD-10-CM > S00-T88 > T51-T65 > T56 > T56.1 > T56.1X > T56.1X4 T56.1X4 Toxic effect of mercury and its compounds, undetermined Non-Billable/Non-Specific Codes T56.1X4A..., initial encounterT56.1X4D..., subsequent encounterT56.1X4S..., sequela