title: Measuring cortisol and DHEA in fingernails: a pilot study.
abstract: OBJECTIVE
  Abnormalities in both cortisol and dehydroepiandrosterone (DHEA) have been reported in psychiatric disorders. Analysis of saliva, urine and blood cortisol and DHEA levels provides an index of hormone levels over a short time period. Unlike such conventional measures, fingernails incorporate endogenous hormones that passively diffuse to the nail matrix from capillaries during keratinization. This study piloted the measurement of cortisol and DHEA levels in fingernails as a potential measure of their accumulated secretion of steroid hormones over a prolonged time period.
  
  
  METHODS
  Thirty-three university students (18-24 years) provided fingernail samples on two occasions over a school semester. The visits were scheduled so nail cortisol and DHEA levels were collected from periods when students might be under different levels of stress.
  
  
  RESULTS
  DURING THE PUTATIVELY STRESSFUL PERIOD, THE NAIL SAMPLES SHOWED A SIGNIFICANT INCREASE IN THE CORTISOL: DHEA ratio (P = 0.0002) due to a significant decrease in the DHEA levels (P = 0.004) and a numerical but not statistically significant increase in the cortisol levels (P = 0.256).
  
  
  CONCLUSIONS
  This pilot study showed that nails can be used to measure cortisol and DHEA, a measure which may reflect environmental stress. More work is required to further validate this technique which may prove useful in studies of both healthy individuals and patient groups.
authors.affiliation: Developmental Neuroscience and Child Health, BC Children's Hospital, Vancouver, BC, Canada.
authors.forename: Fay
authors.initials: F
authors.lastname: Warnock
authors.forename: Kevin
authors.initials: K
authors.lastname: McElwee
authors.forename: Rubo J
authors.initials: RJ
authors.lastname: Seo
authors.forename: Sean
authors.initials: S
authors.lastname: McIsaac
authors.forename: Danielle
authors.initials: D
authors.lastname: Seim
authors.forename: Tatiana
authors.initials: T
authors.lastname: Ramirez-Aponte
authors.forename: Karine An
authors.initials: KA
authors.lastname: Macritchie
authors.forename: Allan H
authors.initials: AH
authors.lastname: Young