Molybdenum in infancy: Methodical investigation of urinary excretion

Project: inical evaluation of trace element metabolism in infancy is based on optimal pre-analytical procedures. Urinary molybdenum excretion, the major determinant of its retention, was investigated to deduce criteria for representative specimen collection. ures: lybdenum concentration was analyzed in 24-hour urinary specimens (n = 193) to evaluate the range in pediatric patients. 2.) In 20 children aged 0.4 to 9.3 (mean 2.3) years admitted for a micturition cystourethrogram, three urinary collection methods (catheter, spontaneous midstream samples, urinary collection bags) were compared. 3.) Diurnal variations of molybdenum concentration were assessed by fractional urinary collection in preterm infants fed infant formula or human milk (n = 10). Analysis was performed using atomic absorption spectroscopy. s: e molybdenum concentration in 24hour specimens was 4.0 (0–123) μg Mo/l. 2.) Urine gained by catheter collection (n = 20) rendered 7.0 (0.5–60.1) μg Mo/l, midstream samples and the use of urinary collection bags showed a concentration of 21.25 (0–91) μg Mo/l (p > 0.05). 3.) Fractional collection over 72 hours rendered a significant increase in only one participant. Diurnal differences of the urinary molybdenum concentration were significant between 3–6 p.m. and 6–9 p.m.. The molybdenum/creatinine quotient differed between the time intervals 3–6 p.m. and 9–12 p.m., as well as 9–12 a.m. and 6–9 a.m. (p < 0.05). sion: ric routine procedures are suitable for the assessment of urinary molybdenum excretion. The diurnal variations assessed are of minor clinical relevance, but should be considered by respective definition of collecting times and reference values.