MON-LB047 GH Values in Serum and Blood Spots on Filter Paper Samples in Infants until 60 Days of Life by Electrochemiluminescence (ECLIA)

Abstract

Congenital 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. Severe neonatal GHD needs a fast diagnosis and the substitution with recombinant human GH because of the risk the morbi-mortality. 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 born appropriate for gestational age (AGA). Aims: To compare and correlate the GH values in serum and blood spots on filter paper samples in infants until 60 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 blood spot and with hormones of the hypothalamic-pituitary-gonadal and adrenal axis. Subjects and methods: We analyzed 301 serum and whole blood spots samples obtained from AGA neonates between 2-60 days of life (2-15 days n=216, 16-30 days n=65 and 31-60 days n=20 (F: 154, M: 147). GH concentrations were measured by ECLIA Roche C600, which is calibrated against the 2 nd International Standard Code 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. The statistical analysis was performed by Spearman correlation coefficient. Results: 2-5 days: serum GH (ng/mL) mean value (SD): 20.81(15.8); P5: 6.30, P95: 42.30; 6-15 days : mean GH value 8.78 (4.34); P5: 3.29, P95: 15.19; 16-30 days: mean GH value: F: 10.55 (4.58), M: 7.72 (3.75) and 31-60 days: mean GH value: F: 4.67 (2.75), M 6.82 (4.57). Blood spots GH (ng/mL) mean value (SD): 2-5 days: 17.58 (9.95); P5: 5.68, P95: 33.60; 6-15 days: mean GH value: 10.31 (5.88), P5: 3.0, P95: 21.02; 16-30 days: mean GH value: F: 10.41 (6.01), M: 10.99 (7.78) and 31-60 days : mean GH value: 7.02 (5.25), M 9.12 (8.08). The Spearman correlation obtained between both techniques in parallel measurements was r2=0.85 (p< 0.0001). Conclusions: In agreement with different reports, our results showed high average GH levels in the first few days of life. Human GH secretion is pulsatile from the very beginning, however, newborn screening card spotted with blood during the first week of life, when neonatal hypersomatotropism is present, 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 type of samples would indicate that the measurement of GH in dried blood spot sample...