The number of blood donors in Scotland is at a record low, new figures show.
Last year, more than 26,000 people gave blood on three occasions
Some 10,000 fewer people came forward to make donations this year, compared to the figure for 2006.
The 15% fall has prompted the Scottish National Blood Transfusion Service (SNBTS) to call on donors to commit to giving blood three times a year.
The service provides transfusions for more than 100,000 patients a year but Hogmanay is one of the busiest nights for accident and emergency wards.
Donations can drop off by about 20% over the New Year period but donor centres in Glasgow and Edinburgh will be open until lunchtime on Hogmanay.
The SNBTS appealed to donors to make the Three Times Promise their New Year's resolution.
Just over 26,000 people - or 15% of donors - gave blood on three occasions in 2007. They must leave at least 12 weeks between donations.
The SNBTS revealed that Blood Donor 24 - a group of 10,000 donors across the central belt - have been called on 13 times in the past year to remedy specific blood shortages in groups A negative, O positive and O negative.
A&E wards rely on O negative blood for emergency procedures because it is the only blood group that can be safely transfused to anyone when there is no time to match the patient's blood group.
Only 9% of people in Scotland have O negative blood.
The SNBTS said the fall in donors meant it had to expand its base to 197,000 active donors over the coming year.
Moira Carter, national donor services manager for SNBTS, said: "Overall 10,000 fewer donors came along to donate this year, which reflects a very worrying trend. It is essential that we reverse this."