Early postnatal point-of-care glucose screening in late preterm neonates of 35-36 weeks gestation

Background: Late preterm (LPT) neonates have been shown to be at higher risk for hypoglycemia compared with term neonates. Aims: To characterize postnatal values for point-of-care glucose (POCG) screening in late preterm neonates with a gestational age of 35-36 weeks, to assess the impact of additional risk factors in the development of POCG values ≤45 mg/dL in LPT neonates, and to compare laboratory and POCG values. Study design: POCG values were determined during the first 12 hours of life, and percentile trend lines were determined. LPT neonates were assigned to one of two groups: (1) no additional risk factors for POCG values ≤45 mg/dL (≤2.5 mmol/L); (2) at least one additional risk factor. Term neonates with pre-determined risk factors for hypoglycemia were screened at least once. Screening results were compared with laboratory determinations if the samples were obtained with 8 minutes of each other. Subjects: 238 LPT neonates with a gestational age of 35-36 weeks admitted to a newborn nursery. Outcome measures: POCG values and laboratory glucose values related to postnatal age; associated risk factors for POCG values were ≤45 mg/dL. Results: Minimum and 10th percentile values during the study period ranged from 20-48 mg/dL (1.1-2.7 mmol/L) and 36-59 mg/dL (2.0-2.3 mmol/L), respectively. No significant differences in incidence or distribution of POCG values ≤45 mg/dL were noted between the two groups. Values ≤45 mg/dL were noted frequently following an initial value >45 mg/dL. POCG values tended to be higher than laboratory glucose values, particularly in the lower range. The incidence of hypoglycemia in LPT infants was similar to the incidence in full-term infants with risk factors. Conclusions: Given the tendency for POCG to over-estimate laboratory glucose, the actual incidence of hypoglycemia in this cohort may be higher than we have reported. All neonates with gestational age 35-36 weeks should be monitored closely for hypoglycemia, and a single screening value after delivery is inadequate.