As multiple GFETssig and GFETsref were integrated on the chips, the output of the differential measurement ΔVDP was considered to be the difference between the group means. We used Bayesian estimation to calculate ΔVDP for the two groups. By assuming that the obtained VDP followed normal distributions (VDP, D ~ N(μD, σD 2 ), where μ and σ are the mean and standard deviation and the subscript D is sig or ref, the posterior distributions of (μsig, σsig) and (μref, σref) were inferred by using Markov chain Monte Carlo (MCMC) methods. From the MCMC sample, we examined the credible difference of means (ΔVDP = μsigμref). The discrepancy between the GFETssig and GFETsref structures resulted in non-zero values of ΔVDP. Therefore, the offset voltage was subtracted to calculate the net signal (S). The offset voltage was determined as the mean value of ΔVDP based on blank sample measurements (ΔVDP, 0nM). Thus, S is given by S = ΔVDP -ΔVDP, 0nM. The noise floor was defined as 3σN, where σN is the standard deviation of S for blank samples.