A pint of whole blood fetches about $100, but broken into various components, might bring in $190, depending on the region in which it is sold.

Plasma, valued for its relatively long shelf life, is what remains when the platelets and oxygen-carrying red cells are removed from blood. One can extract about $55 worth of it from a pint of whole blood. And it can be separated further -- into albumin, which is used to keep blood-vessel walls from collapsing after an injury; Factor VIII, a blood-clotting agent used by hemophiliacs, and immune globulins, which can be used to strengthen the human immune system against certain diseases.

Collecting and further processing plasma is no easy matter. Commercial companies typically pay donors, because separating the plasma from the whole blood, which is done at the bedside, can take as long as three hours. That and further processing require a sizable investment in technology and training. As a result, only the largest nonprofit organizations -- often in collaboration with profit-making companies -- have entered the market for plasma products.

Plasma is the fastest-growing segment of the blood-products industry. It is a global market which last year had revenues of about $2 billion, according to Jack M. Reasor, president of the Marketing Research Bureau of Laguna Beach, Calif., which studies plasma collection in 30 countries. Five international companies dominate the market. But the United States is the major producer of plasma, collecting more than 60 percent of the world's annual yield of 15 million liters.

The industry leader for plasma products, with about 30 percent of the market, is the Armour Pharmaceutical Company of Bluebell, Penn., a subsidiary of Rhone-Poulenc Rorer, the big French Government-owned pharmaceutical company.

Next is Hyland Therapeutics of Glendale, Calif., a subsidiary of Baxter International Inc., which has 25 percent. Cutter Laboratories, a subsidiary of Miles, which is in turn a division of Germany's Bayer A.G., has 15 percent of the market, followed by Alpha Therapeutic, a subsidiary of Japan's Green Cross Corporation, with 10 percent.

The Red Cross took a bold step in 1978 by contracting to use the manufacturing facilities of Hyland, thus entering the commercial plasma market with its donated plasma supplies. That business, which now accounts for about half Hyland's output, brought the Red Cross roughly $100 million of tax-exempt revenues last year. New Complexities The Technology In the Age of AIDS