T59.824DToxic effect of hexamethylene diisocyanate, undetermined, subsequent encounter

T59.824D is the ICD-10-CM diagnosis code for toxic effect of hexamethylene diisocyanate, undetermined, subsequent encounter. It belongs to category T59 (toxic effect of other gases, fumes and vapors), block T51-T65 (toxic effects of substances chiefly nonmedicinal as to source) and chapter 19 (injury, poisoning and certain other consequences of external causes). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

The 7th character "D" means subsequent encounter: use it for encounters after active treatment, while the patient is healing or recovering.

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 949 (Aftercare with CC/MCC, relative weight 1.123) and DRG 950 (Aftercare without CC/MCC, relative weight 0.7664), in MDC 23 (Factors Influencing Health Status and Other Contacts with Health Services), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It is exempt from present-on-admission (POA) reporting, so no POA indicator is required.

It was added in FY2027, effective October 1, 2026.