Changes in biochemistry over time. A. Serum folate. B. Red-cell folate. C. Serum vitamin B12. D. Serum total homocysteine. E. Total bilirubin. F. Lactate dehydrogenase. The dotted lines in panels A to C are the minimum normals according to Bates and Lewis (2012). The short-dashed line in panel D is the maximum limit for patients with high coronary risk factors (Stanger et al. 2004), and the long-dashed line in panel D is the maximum limit in case of normal coronary risk factors (Brouwer et al. 1998). The dashed lines in panels E and F are maximum normals quoted by the testing laboratory.