Six-year freezer test shows stress hormone markers remain reliable
Researchers found that cortisol and cortisone in frozen saliva samples remain stable for at least six years at standard laboratory temperatures, with 96-98% agreement between initial and repeat measurements. The finding validates long-term biobank storage practices for stress and endocrine research, reducing costs for studies requiring delayed sample analysis.
Originaltitel: Salivary cortisol and cortisone are stable after long-term storage
<p>Frozen saliva samples are often used for later determination of salivary glucocorticoids in research studies on stress and endocrine disorders. We studied the stability of cortisol and cortisone in saliva after six years of storage at −80 °C by repeated analysis of 153 stored aliquots, collected with Salivette®, using liquid chromatography tandem mass spectrometry. We found a very high agreement between the first and the repeated measurement after six years at −80 °C, for both cortisol and cortisone concentrations (rs= 0.96 and rs= 0.98, respectively). Passing-Bablok regression equations were y = 0.02 + 1.00x and y = 0.02 + 1.14x for cortisol and cortisone, respectively. We conclude that salivary cortisol and cortisone concentrations remain essentially unaltered after six years of storage at −80 °C.</p>