QD (every day)

How to read it

The Minnesota Board of Pharmacy gives q.d. as quaque die, “every day”. The Joint Commission, which accredits health care organizations, created its “Do Not Use” list in 2004; Q.D., QD, q.d. and qd are on it alongside Q.O.D., QOD, q.o.d. and qod (every other day). Its reason is that the two are mistaken for each other: the period after the Q is mistaken for an I, and the O is mistaken for an I. The replacement wording on the list is “daily” and “every other day”. ISMP marks QD the same way on its own list, where the recommended wording is “daily”.

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How QD gets misread

ISMP’s list of error-prone abbreviations says QD is mistaken as q.i.d., four times a day (QID), “especially if the period after the q or the tail of a handwritten q is misunderstood as the letter i”. ISMP Canada’s “Do Not Use” list adds that the Q has been misread as the number 2. The Pennsylvania Patient Safety Authority’s 2005 advisory gave cases from its reporting system: an order written QD that was read as QID, and an order for QOD (every other day) that was given every day.

QOD, q1d and OD

Other ways of writing “daily” are flagged too. ISMP lists QOD as mistaken for qd or qid “especially if the ‘o’ is poorly written”, and q1d (daily) as mistaken for qid. OD for “once daily” is on the lists of both ISMP and ISMP Canada because it is also the abbreviation for the right eye (oculus dexter); ISMP records oral liquid medicines being put in the eye as a result. In Britain OD is still a common shorthand: Rowcroft Hospice’s guide for new prescribers gives OD (omni die) as “every day”.