Canadian Blood Services is asking Prince Edward Islanders to donate blood due to a Canada-wide blood shortage.
National inventories are at a five-year low and officials expect donations will be down all summer.
On P.E.I., warm weather and the extra-long weekend have combined to push down the current level of bookings.
Peter MacDonald, director of donor services in Atlantic Canada says a Canada Day clinic scheduled for Charlottetown was only booked to 35 per cent of capacity.
"Across Canada right now we have 7,500 vacant appointments, so it's not just in Charlottetown," said MacDonald.
"But between today and the end of this week, there's actually 195 empty slots for people to give blood in Charlottetown, so we really need people to heed the call."
The Canada Day clinic at Canadian Blood Services on Fitzroy Street in Charlottetown runs from 9 a.m. to 1 p.m. Call 1-888-2-DONATE to book.