Real-world stability of salivary cortisol and cortisone samples

Silothabo Dliso; Julie Park; Alena Shantsila; Joanne Blair

doi:10.1530/endoabs.111.P81

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Endocrine Abstracts (2025) 111 P81 | DOI: 10.1530/endoabs.111.P81

BSPED2025 Poster Presentations Adrenal 2 (9 abstracts)

Real-world stability of salivary cortisol and cortisone samples

Silothabo Dliso ¹ , Julie Park ¹ , Alena Shantsila ² & Joanne Blair ¹

Author affiliations

¹Alder Hey Children’s NHS Foundation Trust, Liverpool, United Kingdom; ²University of Liverpool, Liverpool, United Kingdom

Background: Salivary cortisol (SC) and cortisone (SCn) samples are stable under a range of laboratory conditions, although high temperatures lead to faster degradation of samples and decreased stability. Sample stability in ‘real world’ environments is required to assess the impact of exposure to elements that may not be examined in a controlled laboratory environment.

Aim: To report stability of SC and SCn in samples returned to the laboratory by post and car journeys.

Methods: Three sets of samples collected from adult volunteers: One control sample stored in the laboratory at -80°C, one posted by second-class Royal Mail, and one transported by 30-minute car journey. SPSS was used for data analysis; Difference between measurements was tested by paired T-test for normally distributed data, Wilcoxon test for non-normally distributed data. Samples collected during the cooler Winter months and hot Spring months were also examined separately by Pearson’s (r) for normally distributed data and Spearman’s correlation (p) for non-normally distributed data.

Results: n = 18, contributed 66 samples (22 per group)

Table 1 Median (range) SC and SCn concentrations in control, car and postal samples
	SC Control (nmol/)	SC post (nmol/)	SC car (nmol/l)	SCn Control (nmol/)	SCn post (nmol/l)	SCn car (nmol/l)
All Samples	5.0(1.1-9.3)	5.0(0.4-7.0)	4.0(1.0-7.0)	25.0(10.5-43.8)	*22.0(0.3-35.1)	25.0(9.6-35.1)
Winter Samples	5.0(2.0-9.3)	4.0(2.7-6.7)	5.0(3.1-6.9)	24.0(16.6-36.8)	21.0(18.7-35.1)	22.0(16.2-30.2)
Spring Samples	5.0(1.1-8.3)	5.0(0.4-7.0)	4.0(1.0-7.0)	28.0(10.5-43.8)	23.0(0.3-34.7)	27.0(9.6-35.1)
* P <.05

Table 2 SC and SCn correlation of car and postal samples with control samples.
	SC post	SC car	SCn post	SCn car
All Samples	P = 515*	r = 0.534*	r = 0.575*	r = 0.341
Winter Samples (n = 8)	r = 879*	r = 0.758*	r = 0.935*	r = 0.781*
Spring Samples (n = 14)	P = 0.336	r = 0.444	P = 0.336	r = 0.444
* P <.05

Conclusion: There was no significant difference between control samples and those transported by car or post. Conversely, correlation analysis indicated that samples returned to the laboratory during warm weather may deteriorate during transport. We recommend that samples be frozen in household freezer before returning samples by car or first-class post, in the first postal collection of the day, Monday – Thursday only.