William N. Pearson

Clinical Usefulness of the Oral Ascorbic Acid Tolerance Test in Scurvy

T IlE ascorbic acid content of blood serum (or plasma) reflects within limits the dietary intake of this nutrient. When, however, the concentration approaches zero the simple demonstration of an absence of vitamin C from the serum does not permit one to predict the tissue stores of the vitamin. The concentration of ascorbic acid in the plasma approaches zero some weeks prior to the appearance of clinically detectable lesions of scurvy.’ The ascorbic acid content of the white cellplatelet layer is a somewhat more sensitive index of tissue stores, but this tedious and difficult determination is not readily adapted to routine use. There is need for a simple, reliable and informative measure of ascorbic acid nutriture whenever the concentration of the vitamin in the serum has dropped to the vanishing point. Several years ago the reports of Wolfer et al.,2 Butler and Cushman3 and Kajdi4 attracted the attention of one of us toward the possibility of using a “saturation” or “tolerance” type of test to estimate tissue levels of the vitamin. Usefulness was noted of one such procedure which measures serum ascorbic acid in establishing the diagnosis of scurvy in adults’ but the evidence for this usefulness in spontaneously developing scurvy has not previously been published. The purpose of this report is to present