Mass Spectrometry Analysis of Urinary Methylmalonic Acid to Screen for Metabolic Vitamin B <sub>12</sub> Deficiency in Older Adults
Michel Boutin, Nancy Presse, Tristan Martineau, Audrey Perreault, Pierrette Gaudreau, Christiane Auray‐Blais
Abstract
Aim: Vitamin B12 deficiency is characterized metabolically by increased serum and urine methylmalonic acid (MMA). Urinary MMA/creatinine ratio is suggested for screening for metabolic vitamin B12 deficiency in older populations. Results: A UPLC–MS/MS method for the analysis of urinary MMA and creatinine was developed/validated. A good separation of MMA from succinic acid, its structural isomer, was achieved. Intra- and interday accuracy biases and precision coefficients were all ≤6.3% for MMA and creatinine. Urine and serum samples of 34 individuals of the NuAge Biobank were analyzed for technical comparisons showing that urinary MMA/creatinine ratios by UPLC–MS/MS strongly correlated with GC–MS values, and with serum MMA values. Conclusion: The UPLC–MS/MS method developed is rapid/reliable for the analysis of urinary MMA/creatinine ratios.Graphical abstract