ESPE Abstracts

Background: In boys with suspected delayed puberty, serum testosterone is used for the evaluation of gonadal function. It is known that early in puberty testosterone levels show a sleep wake rhythm, with nocturnal levels increasing ahead of daytime levels. To evaluate the onset of puberty, the use of salivary testosterone would be an appealing alternative to serum analysis as it is non-invasive and allows multiple nocturnal sampling. Moreover, it is thought that salivary testosterone reflects the free fraction of plasma testosterone. To the best of our knowledge, to date there are no publications regarding cut of values for nocturnal salivary testosterone using Liquid Chromatography Tandem Mass Spectometry (LC-MS/MS).

Objective and hypotheses: Our study aimed to establish cut-off values of salivary testosterone in preadolescent boys and adult men at 03.00 a.m. and 08.00 a.m.

Method: Salivary testosterone levels were determined in twenty healthy preadolescent boys, in the age of six until nine years, and nineteen adult men in the age group eighteen until forty years, at 03.00 a.m. and 08.00 a.m., using LC-MS/MS.

Results: Salivary testosterone levels in preadolescent boys were median 47 pmol/L, with a reference interval of 14 – 127 pmol/L (p2.5 – p97.5) at 03.00 a.m. and at 08.00 a.m. median 49 pmol/L, with a reference interval of 10 – 155 pmol/L (p2.5 – p97.5). In adult men levels of salivary testosterone were median 260 pmol/L, with a reference interval of 84 – 540 pmol/L (p2.5 – p97.5) at 03.00 a.m. and at 08.00 a.m. median 300 pmol/L, with a reference interval of 90 – 1480 pmol/L (p2.5 – p97.5). As these reference values overlap, cut-off values were defined, being 70 and 170 pmol/L. Based on these cut-off values 81% of samples can be correctly classified as being pre- or post pubertal.

Conclusion: We established cut-off values for nocturnal salivary testosterone to evaluate pubertal status.