Uric Acid a Normal Constituent of Blood
Up till quite recently it was held that in normal persons the amount of uric acid in the blood was too small to be detected; also that uric acid was not demonstrable in the blood of normal individuals when on a purin-free diet. On the other hand, if the subject’s blood was found to contain uric acid, while on a purin-free diet, it was held a characteristic feature of gout and of prime diagnostic import.
But, since the introduction of Folin and Denis’s method, it has been established that uric acid is constantly present, in demonstrable amounts, in human blood. These authorities, using their colorimetric method, found that the uric acid content of the blood ranged from 0·7-3·7 mg. per 100 grams. They believe that 1-2 mg. of uric acid per 100 grams of blood is well within the normal variations, but “are not prepared to say that they represent the full variations.”
However, before applying their colorimetric method to human subjects, Folin and Denis conducted some researches into the uric acid blood content of a variety of animals, the results of which appear in the following table:—