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Cortisol level interpretation
About three months ago I was seen at the Mayo Clinic in Rochester for extreme fatigue. They found that my cortisol was low, a 5.8 with a reference range of 7-20 (the blood was taken at 10am). I was told to follow up with my regular doctor in three months, which I just did, to have another cortisol test. My doctor said if it came back low again I would be referred to an endocrinologist. This time it came back a 4.8, even lower than last time. Blood was drawn at 8:30am. However, I just got a letter from my doctor saying my cortisol looks like it’s back within normal range, with the reference range listed at 4.8-20. Can someone maybe explain to me how the reference range changed? This isn’t me being sarcastic, I genuinely want to know how the reference range could change like that. I know cortisol levels vary throughout the day but I was told they are supposed to be highest that early in the morning or something like that. I’m too afraid to ask my doctor about it because I have gone through so many doctors now trying to figure out what is wrong and I don’t want my doctor to think I’m a hypochondriac or something so I figured I would ask here. Thank you in advance to anyone who can give me any info on this!
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@beanie300, I would be as confused as you are. This reference from the University of Rochester Medical Center confirms your understanding about reference levels and time a day fluctuations.
- Cortisol https://www.urmc.rochester.edu/encyclopedia/content.aspx
I encourage you to ask your doctor about the interpretation of the results. Also inquire whether the results will be forwarded to your doctor at Mayo Clinic.
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1 ReactionI am having the same issue. I recently had a tumor removed from or attached to my pituitary gland. My cortisol levels have ranged from 20 (pre-surgery) to 15 (post-surgery) and in between. My doctor says I have adrenal insufficiency but when I get test results results back they show me in the normal range. I don't know what or whom to believe. Is there an acceptable level of cortisol? All of my tests have been done in the early morning. I have also been told that I need to get a medical alert bracelet for this condition.
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1 ReactionWow 🤯 I am so shocked to see this is happening to someone else!!! What if you are the EXACT low number they still say within normal range!!!!& symptoms don’t even matter to them anymore and they go home and have a NORMAL life!!!! Ughhhh
@dbrfactor welcome to Mayo Clinic Connect! Sorry that you are “shocked” to see that someone has experienced something similar to you. Actually that is one of the purposes for Mayo Clinic Connect. We share our stories to let others know that they aren’t alone in the things they are going through. This way we can support and encourage each other. Please not this discussion originated in 2019 (nearly 5 - 6 years ago). The comments before yours are from that time also. The discussion has gone dormant since then until your comment. Hopefully other members will notice your comment and this discussion will soon be revived. If you don’t mind sharing are you currently being treated for adrenal problems and cortisol numbers that are off?
“Please note (not not) this discussion……”
Don't ever trust the doctors to your own research. I have been misdiagnosed with Lyme and adrenal insufficiency. Back in 2014 they said I was just getting old I was complaining about my symptoms for about 8 months so I did my own research and my own lab work and found out it was lyme. I had it for about a year before I got treated and now I have long-term complications.
With my adrenal insufficiency, I had the same problem with my endocrinologist telling me that my cortisol was normal. It came back as 8 mcg. in the morning. But I did my own research and did blood work for DHEA-S and ACTH which both came back low.
She's finally having me go for a ACT stim test.
Before I was finally referred to an endocrinologist, my PCP was telling me I was just getting older with all my symptoms that I described to him for 3 years!
So don't ever trust doctors,do your own research and blood work that you can buy online.
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5 ReactionsI am so glad that you are being proactive. I experienced the same thing. I trusted my doctors to do their best. I have been to 5 endocrinologists. The first one was exceptional. He prescribed Levothyroxine and later (GH) but delayed and moved away. Did not see another endocrinologist 18 years. The next wanted to dose via TSH and dropped my dose twice. I had to leave as he made me sick. Third endocrinologist asked me when my periods stopped and when I said age 38 she replied ‘you just might be hypopituitary’ but never took her labs due to COVID. She left and next doctor ran tests and said drop your dose or leave. I left. Last endocrinologist ran her tests and ditto. No one checks my growth hormone except the first endocrinologist in 1996.
In 2025 the crashing started. Walk 4 miles. Next day less. Then rest etc from April to July then walking pneumonia and meds and rest then short walks in neighborhood had to lay down on friends driveway for my husband to pick me up and then 8.30.25 collapsed in TARGET (blackout). 8.31.25 ER requested cortisol level and they declined because I had high blood pressure.
I have done my own research too and ran my own labs and another ER ran a chest X-ray that they were concerned about and rightfully so as I have not had GH since 1993 car wreck. A 2021 lab indicated IGF-1 LOW GH. My TSH is always low because I am hypopituitary per endocrinologist 1995. I know for a fact my periods stopped age 38 and I have no hair on my legs or armpits and pubic is thin due to LOW LH and FSH.
I am Panhypopituitary with secondary adrenal insufficiency and I can pass out with high blood pressure because my aldosterone is intact. Relative blood pressure must be considered versus high or low so I am now keeping a chart.
I highly recommend that everyone be proactive with their health or you will find yourself not receiving proper medical care since (for me 1996) forever.
Now I am again trying to find an endocrinologist who will not try to revive my TSH level, discover my LOW GH, and LOW ACTH and prevent all my trips to ER with HBP and headache after exertion from my hikes (3 times) and passing out after my one and only 5K (I was 12th) and the firemen were awesome.
GOD is GOOD. AMEN.
My untreated LOW GH is responsible for my LOW good cholesterol and my HIGH bad cholesterol. September 2025 had 3 weeks of white stools. Did some research and LOW TSH and LOW GH are the culprits. That 1993 car wreck has sure been unhealthy. By pure dumb luck I ordered a lab on IGF-1 which was low. It is an indicator for GH. Why are doctors not running full panels on HPT, HPA etc and quickly rendering aid?