March 31, 2016
The Cortisol Awakening Response:
The Most Important Marker in Adrenal Function Testing

The timing of the first morning saliva sample is of the utmost importance, as this sample measures the cortisol awakening response (CAR). This is the highest level of cortisol the body will secrete for an entire 24 hour period, and it is very revealing as to the existence or extent of adrenal dysregulation.

In a literature review regarding the CAR, it is clear that collection 30 minutes after awakening will measure the most robust CAR occurring in each individual. Note on the graph below that collection 15 or 45 minutes after awakening misses the peak of cortisol production. Early or late collection will still represent a diurnal cortisol curve that is meaningful, but may not be as clinically informative as a timely collection. Patients may want to set a timer for 30 minutes after awakening in order to meet this timing as precisely as possible.

Some patients struggle with identifying when exactly they are awake, as many people suffer from bouts of wakefulness throughout the night. For the purposes of collecting the CAR, advise your patients that there is a time every morning when the brain is essentially awake and alert to surroundings, time of day, etc. This may occur naturally or with an alarm and does not mean that the patient gets up or out of bed at this time. Collection should occur 30 minutes after the patient is aware of their surroundings regardless of whether they stay in bed, go back to sleep, etc.

The morning cortisol value is so important that Labrix bases the phasing of hypoadrenia upon it. When noon, evening and night cortisol samples are below range, if the AM sample is adequate, the patient is considered phase I, as the adrenal glands in question are still able to secrete adequate cortisol in the morning. This is a very different picture from the patient who has a low AM cortisol value with the same low noon, evening and night cortisol levels.

Diurnal cortisol levels can be tested alone or as a part of any Labrix hormone panel. When testing adrenal function, remember to educate your patients on the importance of timing the AM saliva sample correctly.

  • Chida Y, Steptoe A. Cortisol awakening response and psychosocial factors: a systematic review and meta-analysis Biol Psychol. 2009 Mar;80(3):265-78
  • Clow A, Hucklebridge F, Thorn L. The cortisol awakening response in context. Int Rev Neurobiol. 2010;93:153-75.
  • Fries E, Dettenborn L, Kirschbaum C. The cortisol awakening response (CAR): facts and future directions. Int J Psychophysiol. 2009 Apr;72(1):67-73.

Labrix Clinical Spotlight Series:
Menopause: Fatigue, Insomnia, & Weight Gain

Labrix Director of Clinical Services Robyn Kutka ND discusses common symptoms associated with menopause, and outlines an effective and straightforward testing and treatment approach for female patients.

Labrix Core Training

Join the hundreds of practitioners who have attended Labrix live training events and learn more about these exciting opportunities directly from a Labrix attendee and Dr. Jay Mead, Medical Director and co-founder of Labrix.

Core Training:
Denver, CO
May 14, 2016

Labrix will be conducting the 1st annual Core Training in Denver. Registration is $150 and upon completing this one day training, you will receive a $100 credit on your testing account. Register for Denver Core Training today.

Core Training:
Chicago, IL
October 8, 2016

Labrix staff physicians will be in Chicago on October 8th to present Core Training. Registration is $150 and upon completing this one day training, you will receive a $100 credit on your testing account. Register for Chicago Core Training today.

Irving, TX
March 31-April 2

Come visit the Labrix booth at the American Academy of Environmental Medicine conference in Irving, Texas, this weekend.

Scottsdale, AZ
April 21-24, 2016

Labrix will be in Arizona for the SHEICON conference on April 21-24. Come chat with the our booth representative and learn more about testing with Labrix.

Hollywood, FL
May 19-21, 2016

Labrix Account Representative Tom Lasota will be exhibiting at the A4M conference in May. Swing by our booth to find out what's new with Labrix in 2016.