T45.9Poisoning by, adverse effect of and underdosing of unspecified primarily systemic and hematological agent

T45.9 is the ICD-10-CM diagnosis code for poisoning by, adverse effect of and underdosing of unspecified primarily systemic and hematological agent. It belongs to category T45 (poisoning by, adverse effect of and underdosing of primarily systemic and hematological agents, not elsewhere classified), 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 6 subcodes must be used instead.

Within T45, choose T45.9 (unspecified primarily systemic and hematological agent) only when documentation doesn't support a more specific option: antiallergic and antiemetic drugs (T45.0), antineoplastic and immunosuppressive drugs (T45.1), vitamins (T45.2), enzymes (T45.3), iron and its compounds (T45.4), anticoagulants and antithrombotic drugs (T45.5), fibrinolysis-affecting drugs (T45.6), anticoagulant antagonists, vitamin K and other coagulants (T45.7) and 2 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.