In suspected stroke, what critical time information should you collect?

• A. Time of onset or last known well
• B. Time of day
• C. Time since last meal
• D. Time since last vital sign measurement

Answer: (A)

In suspected stroke, the most important time detail is the exact moment symptoms started or the last time the person was known to be without symptoms. This moment sets the treatment window, because therapies like clot-busting drugs and clot-removal procedures have strict time limits from onset. Knowing when symptoms began tells you whether a patient is eligible for those interventions and helps you mobilize the right teams quickly, including imaging to confirm the diagnosis and determine further steps. If the onset time isn’t known, the last known well time is used to estimate how long the patient has been symptomatic and to guide decisions until imaging provides clarity.

Other times, such as time of day, time since last meal, or time since last vital sign measurement, don’t influence eligibility for acute stroke therapies and don’t define the treatment window.