LHRH test in the assessment of puberty in normal children

We compared the performance of a sensitive immunoradiometric assay for luteinizing hormone (LH) with a standard radioimmunoassay and assessed the utility of a single LH determination after a standard dose of LH-releasing hormone (LHRH) in distinguishing pubertal from prepubertal state. Nocturnal integrated LH concentration and LH response to a standard LHRH test were assessed in 56 normal children aged 6-17 years. For each assay we examined sensitivities at fixed specificities and areas under the receiver-operator characteristic curves. The results show that: (1) the immunoradiometric assay exhibits better test performance; (2) a single blood sample 30, 45, or 60 min after LHRH administration is as useful to distinguish pubertal from prepubertal state in normal children as the peak LH estimated by multiple blood sampling, and (3) a single cutoff level for IRMA LH can be applied to these time points.