diagnostic value of the growth hormonereleasing factor stimulation test growth hormone gh responses to growth hormonereleasing factor grf were evaluated in 55 children with growth failure the study groups consisted of group 1 severe gh deficiency group 2 partial gh deficiency group 3 patients with prior cranial radiation for nonpituitary brain tumors and group 4 children with idiopathic growth failure children in group 1 were unresponsive to grf mean gh peak sem 16 05 ngml higher gh responses to grf were observed in both groups 2 172 41 ngml and 3 104 28 ngml the highest gh responses to grf were observed in group 4 359 43 ngml anova revealed a significant difference between groups f 129 df 3 p less than 001 and further analysis by the scheffe and studentnewmankeuls tests revealed that group 4 was significantly higher than groups 1 2 or 3 p less than 005 these data suggest that grf unresponsiveness is a reliable predictor of severe gh deficiency in patients with partial gh deficiency or idiopathic growth failure the grf gives semiquantitative information about somatotrope responsivity to exogenous stimulation