Figure 2.

Diagnostic algorithm for vitamin B12 deficiency assessment. The vitamin B12 deficiency diagnostic algorithm was based on a consensus of 42 panelists [mean (95% confidence intervals of the agreement level) = 0.76 (0.61 − 0.88)]. * Full blood cell count and serum B12 concentration; § Serum concentrations of holotranscobalamin, methylmalonic acid, total homocysteine, gastrin, antibodies against parietal cells and/or intrinsic factor and specific tests of the respective specialties. Special diagnostic tests are subject to availability.