Laboratory
T3
Triiodothyronine
Risk
ISMP lists T3 as error-prone when used for Tylenol with codeine No. 3: it may be mistaken as liothyronine, which is sometimes referred to as T3.
Safer Alternative
Write "Tylenol with codeine No. 3" or "liothyronine" in full
Example
Free T3 3.5 pg/mL
Source Note
T3 is also used for triiodothyronine/liothyronine; avoid T3 in drug communication unless the intended meaning is explicit.