The American Red Cross yesterday said its blood supplies have reached a "critically low" level in the Washington area, and unless supplies are replenished quickly the shortage could force local hospitals to postpone some scheduled surgery this week.

"This is an extremely serious situation," said Dr. Paul McCurdy, who oversees the Red Cross blood program for the Washington region. "Unless conditions change, area hospitals will be forced to postpone some elective surgery. When we can't supply the blood, they can't do the surgery, and we simply do not have enough blood right now."

So far, no area hospitals have reported delays in surgery because of the blood shortage, McCurdy said, but blood shipments to hospitals are being reduced.

Outside a near-empty walk-in refrigerator yesterday at the Red Cross blood services center at 2025 E. St. NW, a worker carefully placed pint-sized containers of cold O positive blood into a carton for rush delivery to Holy Cross Hospital in Silver Spring. Hospital officials had requested 10 pints but were getting only five."We just can't spare the rest," the attendant said.

The shortage also has Red Cross officials worried about supplying blood in case of a large-scale emergency. "If we had an emergency like Harold McLinton, [Washington Redskin linebacker who died after being hit by a car last year] who required 90 pints of blood the first 24 hours, we would be in serious, serious trouble," McCurdy said. "I would hope and expect that we could handle the emergency, but we would have to scramble to do it."

A large "blood status board" at the Red Cross center painted a poignant picture of the problem yesterday. The letter E -- for emergency low levels -- was marked in bright red grease pencil beside three blood types in high demand. "O positive -- needed 558 pints, on hand 111," the sign read. "O negative -- needed 153, on hand 51. B negative -- needed 49, on hand 21."

"We always have a shortage in January [when demand typically increases and donations decline], but this is the worst I've seen in the six Januarys that I've been here," said McCurdy.

Most of the area's major hospitals depend upon the Red Cross for the bulk of their blood supplies. The Washington region Red Cross supplies blood to 60 hospitals in a broad area including the District of Columbia and 37 counties from central Virginia to northern Maryland and parts of West Virginia. During a normal week, the Red Cross delivers 4,000 pints of blood, Red Cross spokesman Jim MacLeod said. Donations from area residents make up about 3,500 pints of that. The rest comes from other blood regions. Last week, the Washington region had to request an additional 1,300 pints -- an unusually large amount -- from other regions to make up for fewer donations here.

That request alarmed some officials who are worried that donations will remain low while demand for blood jumps. "People who were putting off surgery until after the holidays now are demanding blood," MacLeod said. "Unfortunately, the number of donors is still down."

Anticipating a holiday shortage, the Red Cross built up a 500- to 700-pint reserve shortly before Christmas, McCurdy said, but that extra blood is gone now.

Red Cross officials have begun calling regular donors to ask them to contribute. The agency also launched an emergency drive yesterday that will last until late January. Persons interested in donating blood can call 857-3400 for information.

Red Cross donors are not paid for giving blood. The Red Cross considers itself an intermediary between donors and hospitals, MacLeod said. It does not sell the blood to hospitals, he said, but does charge them a fee for processing that breaks the blood into four components. "One donation could be used to help four different people," said MacLeod.