Vitamin B12 (cobalamin) and folate blood levels in geriatric reference group as measured by two kits

For serum vitamin B12 levels there was little apparent difference between a geriatric healthy reference group and a hospitalized group for the total population studied; however, the hospitalized males did have an increased prevalence of values less than normal range. The frequency distribution for both sexes of the geriatric reference group gave lower range limits than manufacturer's normal range. (68-632 vs 133-708 pmol/L for Becton Dickinson, and 125-609 vs 179-930 pmol/L for Bio-Rad, using 95% non-parametric limits). For folate there was an increased incidence in values of less than normal in the hospitalized group versus the geriatric reference group, but there was no difference in the ranges calculated for the latter compared to either manufacturer's normal range derived from a younger population. Comparison of results by two manufacturers' kit methods confirmed Bio-Rad's claim to increased low-end sensitivity of standard curve in range of clinical interest.