ESPE Abstracts

Growth Hormone deficiency (GHD) in newborn is an infrequent condition, which can cause threat to life due mainly to hypoglycemia that begins in the first week of life. A GH basal level (whether random or associated with spontaneous hypoglycemia) that distinguishes infants with GHD from those with GH sufficiency in the neonatal period is not conclusive. Few data have been reported about the GH measurements in serum and dried blood spots on filter paper samples in healthy neonates.

Aims: To compare and correlate the GH values in serum and blood spots on filter paper samples in neonates until 30 days of life. To establish GH reference values in healthy newborn until 15 days of life. To analyzed the correlation between GH concentrations in serum and whole blood spot and with hormones of the hypothalamic-pituitary-gonadal and adrenal axis.

Subjects and methods: We analyzed 281 serum and whole blood spots samples obtained from AGA neonates between 2-30 days of life (2-5 days n=147, 6-15 days n=69, 16-30 days n=65) (F: 144, M: 137). GH concentrations (ng/mL) were measured by ECLIA Roche C600 (IRP 98/574) in serum as well as eluted from filter paper samples. The mean and SD GH value, P 5.0 and P 95.0 were calculated. Spearman correlation coefficient was used.

Results: Serum mean GH and (SD): 2-5 days: 20.81(15.8); P5: 6.30, P95: 42.30; 6-15 days: 8.78 (4.34); P5: 3.29, P95: 15.19 and 16-30 days: mean GH: F: 10.55 (4.58), M: 7.72 (3.75). Blood spots mean GH and (SD): 2-5 days: 17.58 (9.95); P5: 5.68, P95: 33.60; 6-15 days: 10.31 (5.88), P5: 3.0, P95: 21.02 and 16-30 days: mean GH: F: 10.41 (6.01), M: 10.99 (7.78). The Spearman correlation obtained between both techniques in parallel measurements was r2=0.85 (P< 0.0001). Conclusions: Our results showed high average GH levels in the first few days of life. Newborn screening card spotted with blood during the first week of life provides such high levels that, even at the nadir of GH pulsatility a basal value could contribute to detect GHD accurately. The good correlation obtained between both types of samples would indicate that the measurement of GH in dried blood spot samples is an appropriate and reliable method which can be incorporated in the diagnosis of neonatal GHD. The newborn screening samples may be a valuable resource for retrospectively assessing GH sufficiency if this neonatal window has passed.