Arslan, R.C., Blake, K., Botzet, L., Bürkner, P.C., DeBruine, L., Fiers, T., Grebe, N.M., Hahn, A., Jones, B.C., Marcinkowska, U.M., Mumford, S.L., Penke, L., Roney, J., Schisterman, E. & Stern, J. (2022). Not within spitting distance: salivary immunoassays of estradiol have subpar validity for cycle phase.

Abstract

Salivary steroid immunoassays are widely used in psychoneuroendocrinological studies of menstrual cycle phase, puberty, and menopause. Though manufacturers advertise their assays as suitable, they have not been rigorously validated for these purposes. We collated data from eight studies across >1,200 women and >9,500 time points. Seven studies collected saliva and one collected serum. All assayed estradiol and progesterone and had an independent measure of cycle phase (e.g., cycle day relative to the luteinising hormone surge or a menstrual onset). In serum, all independent cycle phase measures strongly predicted steroid concentrations. In saliva, cycle phase poorly predicted observed estradiol values, which additionally showed an upward bias compared to expectations from serum. For salivary immunoassays of progesterone, predictability from cycle phase was more mixed, but two widely used assays performed poorly. Imputing average serum steroid levels from cycle phase may yield more valid values than several widely used salivary immunoassays.

Nicholas Grebe

Postdoctoral Researcher

I’m an evolutionary anthropologist/psychologist who studies primates big and small, and the biological bases of behavior.