On the processing of saliva samples for progesterone assay

Area of Science:

• Reproductive endocrinology
• Clinical chemistry

Background:

• Saliva progesterone concentration is a recognized biomarker for corpus luteum function.
• Optimal methods for saliva sample preparation and storage for progesterone analysis have not been established.

Purpose of the Study:

• To determine optimal conditions for saliva sample treatment and storage for accurate progesterone analysis.
• To validate saliva progesterone measurements against serum progesterone levels.

Main Methods:

• Saliva samples were sonicated and extracted with hexane using a vortex mixer.
• Saliva samples were stored at room temperature or frozen promptly.
• Progesterone levels in saliva and serum were measured using radioimmunoassay.
• Daily saliva and frequent serum samples were collected from four women throughout their menstrual cycles.

Main Results:

• Sonication created a homogeneous saliva sample, allowing quantitative progesterone removal via single hexane extraction.
• Storage of saliva at room temperature for 48 hours significantly decreased measurable progesterone levels.
• Excellent correlation was observed between progesterone profiles in saliva and serum samples.

Conclusions:

• Optimized sonication and hexane extraction provide accurate progesterone measurement from saliva.
• Prompt freezing of saliva is crucial to prevent progesterone degradation and ensure reliable results.
• Saliva progesterone analysis is a reliable, non-invasive method for assessing corpus luteum function.