Table 2.

The effect of the addition of potential covariates on top of the base model of the venous reading (dependent variable) regressed against the home result (the independent variable). Each additional covariate was added separately and as a full interaction with the home result. Each nested pair of models (without covariate and with) were compared using an analysis of variance. For each nested pairwise comparison of models the dataset used was the full dataset, less any observations that had missing data for either the home result or the added covariate. For further details see Table S2

Additional covariate	P‐value for full interaction cf. base model
Own lancet (Yes = 27, No = 74)	0.40
Type of diabetes (Type 1 = 64, Type 2 = 42)	0.47
Sex (F = 52, M = 53)	0.11
Time between sampling and testing (N = 105) [days (n): 1 (39), 2 (47), 3 (17) and 4(2)]	0.30
Laboratory factor covariate (A = 15, B = 38, C = 1, D = 2, E = 17, F = 13, G = 3, H = 16)	0.016