Floride inhibition in patients with atypical dibucaine-resistant plasmacholinesterase.

The fluoride numbers (FN) of 144 individuals referred to our laboratory for dibucaine number (DN) determinations because of prolonged apnea following succinylcholine in the probands or relatives were determined by our new method using 2.5 X 10(4) M concentration of sodium fluoride at 37 C. Dibucaine-resistant homozygotes and heterozygotes both had lower FN than the normal homozygotes. A linear correlation between DN and FN for all these genotypes was found which is described by the equation FN = 0.59 DN + 32. The correlation coefficient was r = 0.94. This equation will help in the correct identification of atypical fluoride resistant genotypes, since these ought to have an observed FN lower by 2 standard deviations than the FN calculated from this equation.