Abstract
Investigations were made on the reagents used and various conditions of the reaction of varying methods of the quantitative determination of serum total cholesterol with an emphasis on Zak-Kitamura's method which is a modification of the ferric chloride deproteinization.
Results obtained showed that the values determined by Shibata's modification and Tokyo Medical College (TMC) modification were higher than those determined by Zak-Kitamura's modifition, while, the values obtained by Zak's original method, Zlatkis' modification and Kitamura's direct method were lower. Standard deviation, moreover, was large in the case of Zak's original method and TMC modification, while, that of Zlatkis' modification and Shibata's modification was small.
On comparison of those methods by the use of pure cholesterol dissolved in acetic acid, likewise, Shibata's modification and TMC modification showed high values, while Zak's original mothod, Zlatkis' modification and Kitamura's direct method showed low values, but the difference between those methods was small indicating that the presence of serum protein was the main cause of the above mentioned discrepancy and also insisting the importance of deproteinization for the quantitative determination of the total serum cholesterol.
The cold separation method devised by this author has several advantages that it enables the simple separation of protein, takes only a short time for quantitative determination, and moreover, its standard deviation is the smallest among various modifications and, therefore, it can give certain constant figures.
