Reproducibility and Refinement of Urinary LH in the Screening of Progressive Puberty in Girls.

CONTEXT: First-voided urinary LH (FVU-LH) has been suggested as an alternative to GnRH stimulation test for detection of precocious puberty.

OBJECTIVE

To evaluate the reproducibility of FVU-LH, its correlation with basal and GnRH-stimulated gonadotropins, and its diagnostic value for differentiating progressive from nonprogressive puberty.

DESIGN AND

PARTICIPANTS

Clinical and endocrine data were obtained from the medical records of 95 girls with suspected progressive puberty who underwent 2 consecutive FVU-LH tests. In 55 of these participants, GnRH stimulation test was performed close to the FVU-LH test. The reported cutoff levels of 5 IU/L and 1.16 IU/L for GnRH-stimulated LH and FVU-LH, respectively, were used as markers of progressive puberty, clinically defined as bone age advancement of ≥1 year and/or growth velocity SD score ≥2, in addition to thelarche.

RESULTS

The 2 consecutive measurements of FVU-LH were highly correlated (r = 0.830; P < 0.001). The higher of the 2 results was better correlated with basal gonadotropins and GnRH-stimulated LH. Furthermore, it aligned better with the clinical outcome of girls with early thelarche, which supports the approach of double tests of FVU-LH to distinguish progressive from nonprogressive puberty. By comparison to GnRH-stimulated LH, the higher FVU-LH value had better sensitivity (68%), whereas peak LH had better specificity (91%) for the diagnosis of progressive puberty. Both tests had high positive predictive value and poor negative predictive value.

CONCLUSIONS

The higher value of paired FVU-LH tests can be used to screen girls with suspected progressive puberty and can reduce the need for GnRH stimulation test.