COMPARISON CF GROWTH HORMONE |[lpar]|GH|[rpar]| LEVELS MEASURED BY IMMUNORADIOKETRIC |[lpar]|IRMA|[rpar]| AND IMMUKOFLUORIMETRIC ASSAYS |[lpar]|IFMA|[rpar]| IN CHILDREN WITH SHORT|[period]| STATURE

摘要

Traditionally, the diagnosis of GH deficiency is based on maximal GH values after two stimulation tests under 7 ng/ml measured throuch IRMA. There are now more sensitive methods to measure GH such as IFMA. In this study we compared the GH response measured by IRMA and IFMA in a group of 9 children (3M; 6F) with short stature (SD for stature between -1.2 and -3.7), who were considered normal throuah two pharmacological tests for GH measured bv IRMA. We also assessed by IFMA the GH responses to stimulation tests in patients with proven GH deficiency (transecction of pituitary stalk associated with hypoplastic pituitary and ectopic neurohypophysis or multiple hypothalamic-pituitary Deficiencies) or strong clinical evidence (SD for height <-3.06) and low values of IGF-1. The IRMA and IFMA detection limit was 0.25 ng/ml ana 0.1 ng/ml respectively.In the GH deficient group, the patients had no response to stimulation tests (< 0.1 to 0.2 ng/ml at all times): in two patients the maximal values were 0.8 and 1.7 ng/ml. We observed a positive correlation (r=0.899, p < 0.0001) among the 37 GH samples measured by both methods (GH values ranging from 0.31 to 35.1 ng/ml in IRMA, and from 0.1 to 17.9 ng/ml in IFMA) in the group with normal response. We conclude that the GH values measured by IFMA are lower than by IRMA. Therefore, normal values of GH by this method must be reassessed to avoid misdiagnosis of GH deficiency.