Use of Urine to Serum Fluoride Concentration Ratios to confirm Serum Fluoride Analyses

Abstract

IN 1966 I published1 results showing that the normal concentration of fluoride in human serum is about one-tenth the generally accepted value—that of Singer and Armstrong. Part of the evidence supporting my results was the “at least five-fold discrepancy” that could be shown in their data2 which is most easily explained by an error in the measurement of the serum fluoride. The discrepancy involves the ratio of urine to plasma fluoride concentrations when determined by fluorine-18 as compared with stable fluoride analyses. Because the concentration of fluoride in urine is well established in contrast to that in serum where analysis is much more difficult, it is reasonable to question the latter when there is a discrepancy. Singer and Armstrong3, however, in their recent rebuttal, think that I came to erroneous conclusions because I .directed attention to only two of their analyses, which they now consider aberrant.