Chapter 4, Note 8. Total Blood Potassium

For a large scale investigation—requiring as many as one hundred determinations a day—the technique of separating red cells from plasma appeared to be impractical. In view of the relatively minute amounts of potassium in plasma as compared to cells, we could utilize total blood instead of the cells. It was also found that by diluting the blood 1/10, the values obtained were in the same range as for serum potassium, a fact which permitted the use of the flame photometer without any change in the set up of the apparatus. The blood was diluted with a 1 % acetic acid solution in the pipette used for counting white cells. The pipette was shaken as for the count of cells, and the necessary amount taken from the diluted content. The potassium amount was determined and the result multiplied by 10. While the average value for the total blood was found to be around 38 mEq., values as low as 20 or as high as 60 were seen. (Figs. 214, 215, and 216)

Relationship between serum K+ and total blood K+ permits to recognize the nature of the changes

Fig. 214. Relationship between serum K+ and total blood K+ permits to recognize the nature of the changes concerning the intervention of this element. In a case of periarteritis nodosa, the high values of serum potassium and low values of the total blood potassium indicate an offbalance type D.

Low values of serum potassium and high values of total blood potassium indicate an offbalance

Fig. 215. Low values of serum potassium and high values of total blood potassium indicate an offbalance type A in a case of cancer of the gallbladder.

Low values of potassium in serum and in total blood indicate a quantitative deficiency

Fig. 216. Low values of potassium in serum and in total blood indicate a quantitative deficiency, in a subject with a liver adenocarcinoma. The administration of 40m Eq KC1 daily, for 9 days brought the two curves to normal.