GFR (mL/mln/1.73 m2)

Fig. 1. Glomerular filtration rate vs concen-tration of MMA in serum in 20 patients with impaired renal function Dashed line indicates upper reference limit for concentrations of MMA (0.37 pmol/L) in serum. Each data point is the mean of duplicate determi-nations 1524 CLINICAL CHEMISTRY, Vol.36, No. 8, 1990 nancy, gastrectomy, ileal resection, diseases of the small intestine, diabe-tes mellitus, treatment with cytotoxic or immunosuppressive agents, abnor-mal concentration of erythrocyte fo-late, macrocytosis, hypersegmenta-tion of neutrophils, leukopenia, an