Objective: Prospective evaluation of the relationship between first morning urinary gonadotrophins (uGn) measured by immunoassay and corrected for creatinine (uLH:uCr and uFSH:uCr), and basal serum gonadotropins (sLH and sFSH) and in response to LHRH stimulation test. Prospective evaluation of uGn trend in patients receiving GnRH analogue (GnRH-a; decapeptyl SR, 11.25 mg, every 1012 weeks).
Methods: Enrolled 15 (12M) patients evaluated for delayed puberty, 14 (F) for suspected precocious puberty and 16 (3M) on GnRH-a. Three first morning urine samples of three mornings before the stimulation test or before the GnRH-a injection were collected. For patients on treatment, three samples 5/6 weeks after injections were also collected. Data were expressed as median (range), and analyzed by SPSS v10.0 (P<0.05).
Results: Coefficient of variation (CV) of samples collected before the stimulation test was 0.28 (01.4) for uLH:uCr and 0.26 (0.050.99) for uFSH:uCr. Significant correlations between sLH and uLH:uCr (r=0.7; P<0.001) and between sFSH and uFSH:uCr (r=0.9; P<0.001) were identified.
Based on receiver operator characteristics analysis, a uLH:uCr value of 0.032 IU/mmol as a cut-off would detect a sLH peak >5 UI/l (sensitivity: 87%; specificity: 86%; and area under the curve: 0.89).
For patients on treatment, uLH:UCr CV of samples collected before the injection was 0.29 (0.140.85) and after 5/6 weeks 0.33 (0.040.63), while for uFSH:UCr, respectively, 0.24 (0.130.52) and 0.4 (0.081.3).
Median uLH:UCr and uFSH:UCr values before injections (0.01 and 0.34 IU/mmol) were significantly higher than after 5/6 weeks (0.008 and 0.09 IU/mmol) (P: 0.000 and P: 0.000 respectively).
Conclusion: UGn is a useful, non-invasive instrument for diagnosis and management of pubertal disorders.