Pooling ambulatory saliva cortisol samples over consecutive days – as reliable as arithmetic means
2008 (English)In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, Vol. 68, no 6, 508-512 p.Article in journal (Refereed) Published
Objective: When cortisol measurements are to be studied in large populations, cost-effective analyses are needed. This study aimed at testing whether one pooled cortisol value over three consecutive days is as reliable as using the arithmetic mean of the samples from the same measure points.
Material and methods: Thirty participants aged between 45 and 69 collected saliva in salivettes immediately after awakening (t1), 30 min after awakening (t2) and in the evening (t3) during 3 consecutive days. A fixed volume from each of the samples (t1, t2 and t3) was pooled prior to laboratory analysis. Mean levels over 3 days for t1, t2 and t3 were compared to corresponding levels of pooled vials. Cortisol levels were analysed using a radio immunoassay.
Results: All measures tested had high correlations between mean values and pooled samples, exemplified with diurnal deviation rdif t2–t350.974 (CI 0.946;0.987), and awakening response rdif t2–t150.982 (CI 0.963;0.991). There were no statistical differences between the pooled values and the arithmetic means.
Conclusion: Pooling samples gave as reliable results as arithmetic means did. Pooling samples prior to laboratory analysis is a cost-effective method for measuring general diurnal cortisol variation in field research projects.
Place, publisher, year, edition, pages
2008. Vol. 68, no 6, 508-512 p.
Cortisol, HPA-axis, measurements, methodology, saliva, stress
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:liu:diva-14927DOI: 10.1080/00365510701832229OAI: oai:DiVA.org:liu-14927DiVA: diva2:25615
Original publication: Peter Garvin, John Carstensen and Margareta Kristenson, Pooling ambulatory saliva cortisol samples over consecutive days – as reliable as arithmetic means, 2008, Scandinavian Journal of Clinical and Laboratory Investigation, (68), 6, 508-512. http://dx.doi.org/10.1080/00365510701832229. Copyright © Taylor & Francis Group, an informa business2008-09-302008-09-302014-01-10