The Effect of the Food Intake on the Morning Value of the Citric Acid Concentration of the Blood.

The intake of food in the morning immediately after awakening causes an increase in the Ci-value of the blood serum, measured by Thunberg's enzymatic method. In a series of 10 subjects the lowest increase was 5 %, the highest 32 %, and the mean value 20.6 %. When the method is used for diagnostic purposes in liver diseases, blood samples should be taken on an empty stomach and under so similar conditions as possible.