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Donations of blood platelets are even more in demand than whole blood in the aftermath of superstorm Sandy, officials said.

It’s a request as common as clean-up crews after a storm: Please give blood.

And, indeed, disaster officials have been urging potential donors to step up to replenish East Coast supplies disrupted by superstorm Sandy.

“Patients will still need blood despite the weather,” said Dr. Richard Benjamin, chief medical officer of the American Red Cross. “It is critical that those in unaffected areas make an appointment to donate blood as soon as possible.”

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But what’s also true is that certain blood donors are more sought-after than others, particularly the relatively tiny group of people who donate the most perishable of blood components, the platelets.

 “Red blood cells? We’re in good shape. Platelet donors? Call your local facility,” said Dr. Louis Katz, executive vice president of America’s Blood Centers.

Katz and officials with the Red Cross say the highest demand in the days after the giant storm that struck the Eastern seaboard will be for platelets, the tiny, colorless cell fragments involved in blood clotting. At least 300 blood drives have been canceled in 14 states in Sandy's wake, resulting in a shortfall so far of some 10,700 units of blood and platelets, agency officials said.

Platelets are critical for cancer patients and others who require bone marrow and stem cell transplants, Katz said. Those patients need regular treatments, storm or no storm.

Stored at room temperature, platelets have a shelf life of just five days, compared with the 42 days of refrigerated red blood cells.

So far, supplies of whole blood and platelets have held steady in hard-hit New York, New Jersey and Connecticut, thanks in part to the distribution system that shuttles blood efficiently from one part of the nation to the other.

“The networks that move blood are well-coordinated and well-practiced,” Katz said.

Already, supplies of platelets have been shipped to Sandy-stricken hospitals and blood centers from as far away as the West Coast, said Stephanie Millian, a Red Cross spokeswoman.

But more donations are needed now, officials said. Platelet donors make up only about 3 percent of total donors, said Millian. The AABB, the American blood bank association, says that nearly 11 million volunteers give about 17 million units of blood and blood components each year.

There’s not a shortage of platelets in the storm-stricken region, but there is a need, particularly for rare type AB donors. They make up only 4 percent of the US population, but their plasma, for instance, can be used in anyone.

Donating platelets takes longer than donating whole blood, 2 hours compared with 45 minutes, Katz estimated. But it's just as painless and one platelet donation can provide enough for a full therapeutic dose for a patient in need, the Red Cross says. By contrast, it can take four to six whole blood donations to produce one dose of platelets.

Platelet donors usually know who they are. Because they can give 24 times a year, compared with the six times a year for whole blood, they’re often popular at blood centers, especially after disasters.

“Anybody can volunteer to be a platelet donor,” said Millian. Those interested should call the closest blood center to inquire.

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