T50.9Poisoning by, adverse effect of and underdosing of other and unspecified drugs, medicaments and biological substances

T50.9 is the ICD-10-CM diagnosis code for poisoning by, adverse effect of and underdosing of other and unspecified drugs, medicaments and biological substances. It belongs to category T50 (poisoning by, adverse effect of and underdosing of diuretics and other and unspecified drugs, medicaments and biological substances), block T36-T50 (poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances) and chapter 19 (injury, poisoning and certain other consequences of external causes). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

Within T50, choose T50.9 (other and unspecified drugs, medicaments and biological substances) only when documentation doesn't support a more specific option: mineralocorticoids and their antagonists (T50.0), loop [high-ceiling] diuretics (T50.1), carbonic-anhydrase inhibitors, benzothiadiazides and other diuretics (T50.2), electrolytic, caloric and water-balance agents (T50.3), drugs affecting uric acid metabolism (T50.4), appetite depressants (T50.5), antidotes and chelating agents (T50.6), analeptics and opioid receptor antagonists (T50.7) and 4 more.

Codes in this range require a 7th character: A for initial encounter, D for subsequent encounter and S for sequela. Use placeholder "X" characters to fill any empty positions before the 7th character.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.