Taguchi method for the optimization of three loop mediated isothermal amplification procedures for Tritrichomonas foetus detection

Abstract

Taguchi method was used to optimize loop mediated isothermal amplification tests aimed to amplify segments of the elongation factor 1a1 (tf-ef1a1), the 5,8 ribosomal gene (tf-5,8 r) or the beta tubulin 2 (tf-btub2) from the protozoan parasite Tritrichomonas foetus. L9 orthogonal array and quadratic loss functions that penalize deviations from prediction values revealed the effect of amplification reaction components. Analysis of variance (ANOVA) decomposed the contribution of individual factors to a small Ct. Confirmation experiments established that optimum conditions were predictable, verifiable and reproducible. Primers concentration conditioned the non-specific amplification of tf-ef1a1 while betaine and magnesium concentration contributed to accelerate the time to reach a positive threshold in tf-ef1a1, tf-5,8 r and tf-btub2. The general strategy of simple and robust experimental design holds potential as a general optimization protocol for LAMP tests in every diagnostic laboratory.