Comparison of two substrates in determination of plasma cholinesterase activity & genetic variability.

Two substrates, acetyl thiocholine iodide ATCI and benzoylcholine chloride BCC were compared for the determination of plasma cholinesterase ChE levels and after incorporation of dibucaine and sodium fluoride in the assay, their usefulness in determining plasma ChE genetic variability was assessed in 64 healthy subjects. With both substrates, plasma ChE levels were found to be in the reference range. However, ATCI could detect only two variants with the usual phenotype UU in 60 of 64 [93.75%] subjects whereas with BCC 6 different groups could be determined. Though both substrates are of equal value in estimation of plasma ChE levels, BCC is definitely superior in determining its genetic variants.