New donors do require an appointment due to the length of time your visit will take you (roughly 3-4 hours). You can call to schedule an appointment anytime. Be sure to hydrate really well in the days leading up to your first donation .
In general, no appointment is necessary unless you plan to arrive after 7:00 p.m. However, first-time donors go through a lengthy induction process (paperwork, physical exam, etc.), so making an appointment could help save them some time in waiting for that process to begin.
They do have walk-in hours (I believe from 9am-4pm), but you'll be there for at least 3 hours. Also, if you're new, the medical exam takes an hour to complete. Definitely bring water just in case, and make sure you eat plenty of food in the days leading up to the visit! Also, make sure you're getting iron in your diet, because they'll turn you away for the day if your levels are low.
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