Salivary testosterone: a reliable approach to the diagnosis of male hypogonadism.
OBJECTIVE
This study was to demonstrate that Sal-T is a reliable biomarker of androgen status in the diagnosis of male hypogonadism.


METHODS
In order to validate the salivary testosterone assay (Sal-T), its reproducibility, the agreement with serum free testosterone levels (Free-T), the correlation with other circulating androgen markers (bioavailable testosterone, total testosterone) and cut-off values were defined.


METHODS
We studied 52 eugonadic (E) and 20 hypogonadic (Hy) men. Sal-T was assayed using an adapted radioimmunoassay for serum testosterone. Sal-T concentrations were compared in nine cases before and after citric acid stimulation of salivary flow rate. Free-T and bioavailable testosterone (Bio-T) were calculated by Vermeulen equation and SHBG were determined by binding assay.


RESULTS
Sal-T did not depend on salivary flow rate and morning samples from 07.00 h to 09.00 h were stable. Agreement between Sal-T and Free-T measurements was confirmed in all subjects. Sal-T levels correlated positively with all circulating androgens, showing the best correlation with Free-T in E (r = 0.92) as well as in Hy (r = 0.97). A cut-off value of Sal-T < or = 0.195 nm showed 100% sensibility and specificity to rule out hypogonadism.


CONCLUSIONS
Our data showed that Sal-T is a reliable marker of testosterone bioavailability. The results support the inclusion of this biomarker as a noninvasive approach in the diagnosis of male androgen deficiency.
Arregger
Alejandro L
AL
Endocrine Research Department, Instituto de Investigaciones Médicas A. Lanari, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina.
Contreras
Liliana N
LN
Tumilasci
Omar R
OR
Aquilano
Daniel R
DR
Cardoso
Estela M L
EM
D000328:Adult; D000368:Aged; D001682:Biological Availability; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D016022:Case-Control Studies; D002940:Circadian Rhythm; D019343:Citric Acid / Q000008:administration & dosage; D006801:Humans; D007006:Hypogonadism / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012016:Reference Values; D012463:Saliva / Q000737:chemistry*; D012472:Salivation; D012680:Sensitivity and Specificity; D012709:Serum Albumin / Q000032:analysis; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D013739:Testosterone / Q000032:analysis* / Q000097:blood
D015415:Biomarkers; D012709:Serum Albumin; D012738:Sex Hormone-Binding Globulin; D019343:Citric Acid; D013739:Testosterone