On the stability of salivary progesterone under various conditions of storage

Abstract

The concentrations of progesterone in saliva of women exhibited significant decreases when the fluid was stored in plastic vials for 3 days at room temperature or 37 C. The addition of antibiotics or a variety of metabolic poisons to the saliva prior to storage did not prevent the progesterone decrement. However, the addition of albumin (2 g/dl) was protective, suggesting that the protein impeded adsorption of salivary progesterone by the plastic container. Saliva could be maintained at 37 C for 3 days in glass vials or at −20 C in plastic containers for indefinite periods without loss of progesterone titers. These data indicate that a patient under luteal function assessment may collect saliva samples in glass vials at regular intervals during the latter half of her cycle and store them in the freezer compartment of the refrigerator until shipment by mail to the laboratory for progesterone assay. With special care, plastic vials charged with albumin may also be used.