Endocrine Abstracts

Background: A hydrocortisone day curve can be used to assess a patient's steroid replacement. However the need for venous samples requires patients to be admitted to hospital either over-night or as a day case and tablet times may vary compared to the patients' usual practice.

Objective: The aim of this study was to determine whether patients could collect capillary or salivary cortisol at home and whether these collections were reproducible.

Methods: 13 patients on hydrocortisone were identified and collected samples for a six-point day curve at home (Pre and 1 hour post breakfast, lunch and dinner). A capillary and saliva sample was taken at each time point and the day curve was repeated on three separate occasions. A highly sensitive cortisol assay was used. Two patients were excluded, one due to a missing data point and another due to contamination of the salivary sample. If blood is mixed with the salivary sample the cortisol result is above the limits of the assay. This left 11 patients (M:F 4:7) in the final analysis. The area under the cortisol curve was determined using trapeziums and the areas compared using an ANOVA.

Results: All but two patients collected the samples correctly and invalid curves were easily identifiable. The ANOVA confirmed the reproducibility of the day curves using either capillary (p = 0.30) or salivary (p = 0.12) cortisol measurement.

Conclusions: Capillary and salivary cortisol can both be measured from samples collected by patients in their own home. This leads to a reproducible day curve, avoids the need for hospital admission and tests the patient in their normal environment and on their usual tablet regimen.