Pyruvic Acid I. Collection of Blood for the Determination of Pyruvic and Lactic Acids*

The accurate determination of pyruvic and lactic acids is a matter of considerable theoretical and practical importance. These acids play a role in the metabolism of carbohydrates, and they are found in increased concentration in the blood in conditions of thiamine deficiency. Recently we suggested (1) the determination of the ratio of lactic to pyruvic acid in the blood as a measure of oxidative conditions in tissues, and we have applied it to various studies now in progress dealing with muscular exercise and the reaction of human subjects to high altitude. Large and indeterminate losses, which make the results valueless, may occur during collection and subsequent handling of blood samples, Until recently, samples of blood to be used for this determination have been collected with syringes and then transferred to bottles containing oxalate. Wilkins, Weiss, and Taylor (2) were the first to show that pyruvic acid disappears from such samples. This was confirmed by Bueding and Wortis (3), who suggested the use of sodium monoiodoacetate for the “stabilization” of the pyruvate. Bueding and Goodhart (4) have recently recommended the addition of 1 per cent each of iodoacetate and fluoride to samples of oxalated blood. Consistent results, without apparent loss or gain of pyruvic acid during collection of t.he sample, can be obtained by using a very simple procedure. Blood is withdrawn from the vein by means of 2 or 5 cc. syringes,l and the volume is adjusted to the mark, after which the sample is expelled in a fine stream through the needle into a measured volume of precipitant. The procedure eliminates not only the use of a sample bottle containing oxalate