The ZRT Laboratory Blog

The ZRT Blog is an extensive resource for patients and health care providers searching for health and hormone testing information. Here, you can read about ZRT’s cutting edge research, advances in testing, wellness advice, and health industry highlights.

Cortisol Patterns For Graveyard (Shift) Workers

Posted by Dr. Alison McAllister on Tuesday, 31 October

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If you come by ZRT on Halloween you’re likely to be greeted by a witch, vampire, zombie or other nightcrawler. We take our decorations and dressing up seriously around here, and finding people in costume processing your labs or taking your calls is par for the course.

Laughing aside (and let me tell you, some costumes are hilarious) those who live their lives by night – on the graveyard shift – can really struggle.

Two primary challenges for people who work at night are energy and fatigue. This is largely due to the pineal gland and its interaction with light that triggers and enforces our body’s pre-programmed circadian rhythm – which produces high cortisol in the morning and then drops throughout the day until the lowest value at night. For those who work graveyard shift that normal circadian rhythm must be re-established, and for many people it doesn’t happen.

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Avoiding 3 Common Interpretation Pitfalls for Salivary Cortisol Tests

Posted by Dr. Allison Smith on Tuesday, 08 August

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One of ZRT's most popular tests includes diurnal assessment of a patient's salivary cortisol levels. On the surface, these tests seem easy enough to interpret, but experienced clinicians know there can sometimes be pitfalls.

Patients testing cortisol in a clinical setting may take undisclosed medications, live under stressful conditions, have inflammation, genetic variations, tumors, and diseases. Sleuthing out the cause of cortisol elevations and depressions can be a real challenge.

To avoid unnecessary work-ups, there are a few areas to consider when interpreting a salivary cortisol test – Contamination, Suppression, and Comorbidities.

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Pheochromocytoma - A Rare Condition Exposed by Neurotransmitter Testing

Posted by Dr. Alison McAllister on Wednesday, 28 June

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The New York Times did a remarkable story the other day that ended with the line "When you hear hoofbeats, the chances are good that it's a horse…but we must also remember that sometimes the circus is in town. [1]

ZRT is apparently hosting the circus this year. At the odds of 3-8 individuals per million – ZRT has been instrumental in discovering two cases of pheochromocytoma tumors in the last six months. A condition that my clinical physiology teacher, Dr. Bettenburg, said was so rare that we would never see one, and if we did, we should contact her – so I did, this week. 

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Re-assessing the Notion of "Pregnenolone Steal"

Posted by Dr. Thomas Guilliams on Wednesday, 21 June

ThinkstockPhotos-687447022-pregnenolone-.jpgWhen clinicians measure salivary cortisol and DHEA (DHEA-S) to assess stress and HPA axis function, it is common to find DHEA levels below the reference range in a number of individuals. A common explanation for the depletion of DHEA and other hormones (e.g., progesterone, testosterone) due to chronic stress is the phenomenon known as "pregnenolone steal."

The pregnenolone steal notion states that since all steroid hormones use pregnenolone (derived from cholesterol) as a precursor, the elevated secretion of cortisol caused by acute or chronic stress will inevitably result in less available pregnenolone to serve as a precursor for the production of DHEA and other down-stream hormones.

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