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At the present time there is an enormously increasing demand for albumin. The most common procedure for the isolation of this plasma component is the cold ethanol technique developed by Cohn. Because this process necessarily isolates other blood components for which there is less demand in relation to albumin, albumin production is expensive. Therefore, we have developed a two-step fractionation for the isolation of albumin. It is basically a heat precipitation method with the albumin yield being about 90% of the original plasma albumin. In comparison to cold ethanol methods, it is considerably less expensive. Other blood components, e.g., clotting factors, immunoglobulins, may also be isolated. A nonmodified gamma-globulin for intravenous use is obtained by removing anti-complementary activity with hydroxyethyl starch. Additional fractionation steps are required to isolate these other components, but unlike in established methods, these are not necessary for the isolation of solely albumin.

Human plasma may be separated into five fractions using the method described by Cohn in 1946. Although there are several drawbacks to alcohol precipitation, especially in albumin isolation, it is still used throughout the world. This paper describes an alternative procedure for albumin isolation from plasma or albumin-containing plasma fractions using a combined heat fraction/polyethylene glycol precipitation method. No polyethylene glycol is detected in the final product which is immunoelectrophoretically 100% pure, salt poor, heat resistant during pasteurization, and stable during long-term room temperature storage. The yield is at least 90% of the original plasma albumin. In comparison with the Cohn method, fractionation time and expense are significantly reduced.

Although the heat-ethanol method of fractionation for the isolation of normal serum albumin (NSA) is technically easier and more economic than cold-ethanol methods, globulin removal and albumin concentration remain basic hinderances to a truly simplified procedure. Continuous flow centrifugation for the separation of precipitated proteins has been effectively replaced on the one hand by alluvial filtration (globulins), and onthe other hand by diafiltration (albumin). Through these changes, investive and running costs are further reduced, noise is all but eliminated, albumin yield is somewhat increased, and personnel required for a 600 1 plasma batch is reduced from four workers to one.

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