Comparison of serum total calcium, dialyzable calcium, and dialyzable magnesium in well and sick neonates.

We studied the relation of serum total calcium, dialyzable calcium, and dialyzable magnesium in 61 well and sick newborn infants aged 7-76 h. The infants' serum total calcium, dialyzable calcium and magnesium concentrations (ion chromatography method) were studied in comparison with the infant's history and sickness scale. We found that serum total calcium and dialyzable magnesium were lower in sick infants compared to well infants. Both serum total and dialyzable calcium concentrations initially decreased and then increased by about 30 h of age. Serum dialyzable magnesium concentrations increased with our infants' age. Serum total calcium values correlated significantly with the infant's birth weight, gestational age, 1-min Apgar score, respiratory distress, severity of sickness, serum bilirubin and sodium concentrations.