Predischarge bilirubin screening in glucose-6-phosphate dehydrogenase-deficient neonates.

OBJECTIVE: To assess the validity of predischarge serum bilirubin values in determining or predicting hyperbilirubinemia in glucose-6-phosphate dehydrogenase (G-6-PD)-deficient neonates, and to facilitate appropriate discharge planning. METHODS: Serum total bilirubin values were determined between 44 and 72 hours of life in a cohort of term, healthy neonates at high-risk for G-6-PD deficiency but with no other risk factors for hyperbilirubinemia. Percentile-based bilirubin nomograms were constructed for G-6-PD-deficient infants and normal infants according to age at sampling. The incidence of hyperbilirubinemia (serum bilirubin value > or =256 micromol/L [15 mg/dL]) for each group was determined according to the percentiles for that group. RESULTS: In both G-6-PD-deficient neonates (n = 108) and control neonates (n = 215) with serum bilirubin values <50th percentile for age, the incidence of hyperbilirubinemia was low in the G-6-PD-deficient neonates, with no measurable incidence in the controls. The incidence of hyperbilirubinemia became clinically consequential, and significantly higher in the G-6-PD-deficient groups, when the percentiles were > or =50: for those in the 50% to 74% range the incidence was moderate (23%) for the G-6-PD-deficient and small (7%) for the control infants (relative risk, 3.29; 95% confidence interval, 1.01-10.67). Among those infants > or =75th percentile, 82% of the G-6-PD-deficient infants, compared with 25% of the control infants, were either already hyperbilirubinemic at the time of screening or subsequently developed hyperbilirubinemia (relative risk, 3.23; 95% confidence interval, 1.99-5.24). CONCLUSIONS: Timed, predischarge serum bilirubin screening can be used to identify G-6-PD-deficient neonates at low, intermediate, or high-risk of developing severe neonatal hyperbilirubinemia, and thus offer a selective approach to the discharge and follow-up surveillance of these infants.

Antacid bezoar in a premature infant.

A premature infant with severe enteroviral infection was treated with Maalox for gastric bleeding. Bezoars formed, which were shown to contain high concentrations of magnesium. An association between antacid administration and bezoar formation in neonates has been previously suggested but has not until now been clearly documented.

The rise of serum creatinine levels during labor.

Serum creatinine, blood urea nitrogen and creatine phosphokinase were measured in 32 women during the last 3 weeks of pregnancy and, in a further 39 women, during and after labor. The serum creatinine increased from 61.9 +/- 0.9 to 69.8 +/- 1.8 mumol/l (mean +/- SEM) (P less than 0.05) in the third stage of labor and returned to normal by 72 h after delivery. The muscle creatine phosphokinase increased from 54 +/- 7 to 77 +/- 9.9 units (P less than 0.05) during the third stage and remained high (87 +/- 13.3 units) 72 h later. We conclude that these changes are due to muscle contraction and injury during delivery.

Paraprotein interference with colorimetry of phosphate in serum of some patients with multiple myeloma.

In untreated serum of three patients with multiple myeloma, concentrations of inorganic phosphate ranged from 130 to 270 mg/L as measured with a chromogenic assay based on the interaction of phosphate ion with ammonium molybdate in the presence of ferrous sulfate. There were no clinical features of hyperphosphatemia, and values for total calcium concentration in serum remained within normal limits throughout. Subsequent investigations demonstrated that this hyperphosphatemia was spurious and was caused by high concentrations of the paraprotein interfering with the chromogenic assay. Because this type of assay, adapted for automated systems, is now widely used in clinical laboratories, we call attention to this limitation to avoid confusion in clinical evaluations of patients with multiple myeloma.

Lymphocyte and erythrocyte concentrations of potassium, magnesium and calcium in normal controls.

A direct method for the measurement of potassium, magnesium and calcium in lymphocytes and erythrocytes is presented, using relatively small quantities of human blood. With this method repeated measurements can be carried out in the same individual; this enables one to follow changes in disease states or as a result of drugs.