Fig. 6

Significant impact of the feasibility study results on the annual volumes of six analyses. Comparison of the volumes of tests reported by the Belgian laboratories of clinical pathology for 6 different years: group A (light grey bars, period before the presentation of the results of the feasibility study [data collected for 2014 and 2015]) versus group B (dark grey bars, period after the presentation of the results of the feasibility study [data collected for 2016 and 2017]) versus group C (black bars, period from RLs’ recognition [data collected for 2019 and 2020]). Values were calculated as mean volumes ± SD, n = 2 for the 3 groups (A,B,C) of two successive years. Statistical analyses were performed by one-way ANOVA with Tukey’s posttest for multiple comparisons between the 3 groups. Asterisks indicate values that are statistically significantly different from each other (*p < 0.05). Analyses presented in each panel: a assessment of α-aminoadipic semialdehyde and δ1-piperideine-6-carboxylate in urine; b assessment of B6 vitamers in plasma; c assessment of pterins in urine; d assessment of Complement component Factor B; e assessment of Complement component Factor Bb; f assessment of intra-leukocyte cystine. RLs Reference laboratories