Saliva testing for measuring testosterone levels has gained acceptance as a dependable approach. (Keevil et al., 2014)

According to It can be used in a clinical setting to diagnose and treat hormonal disorders. (Hammerich et al., 2017)

 

Keevil, B. G., MacDonald, P., Macdowall, W., Lee, D. M., Wu, F. C., & NATSAL Team (2014). Salivary testosterone measurement by liquid chromatography tandem mass spectrometry in adult males and females. Annals of clinical biochemistry, 51(Pt 3), 368–378. https://doi.org/10.1177/0004563213506412

Hammerich, K. H., Donahue, T. F., Rosner, I. L., Cullen, J., Kuo, H. C., Hurwitz, L., Chen, Y., Bernstein, M., Coleman, J., Danila, D. C., & Metwalli, A. R. (2017). Alkaline phosphatase velocity predicts overall survival and bone metastasis in patients with castration-resistant prostate cancer. Urologic oncology, 35(7), 460.e21–460.e28. https://doi.org/10.1016/j.urolonc.2017.02.001