Raised serum cortisol level - lab mistake?

[nonemus]

In a recent blood test my cortisol level was shown as well outside the lab reference range but there is no entry in the "normality" column. When I rang the surgery I was told the results (lots of other tests) were all fine but this doesn't seem fine to me. I wonder if the lab have made some mistake.

These aren't routine tests, I have been feeling ill but I don't have high blood pressure. I had thought the test might show low levels!

I think you should make a telephone appointment with your GP. Cortisol levels depend on the time of day. If it is truly high, GP can repeat it at 8/9am after giving you a dose of dexamethasone at 11pm/midnight the previous evening. The early morning cortisol should then be suppressed to a very low level for a normal result. Random cortisols can be hard to interprete so you really need the GP to talk you through it.

the lab reference range showed different figures for the time of day. The blood test was taken in the morning, when cortisol levels would be highest, but was still well above the morning range (over 100 above it). I don't take steroids so with a figure that high I would have expected the lab to mark it as abnormal.