Cortisol blood test

[Clara9]

What time in the morning would be best to catch low cortisol if I have it?

[FallingInReverse]

Everyone is different when it comes to where their own cortisol will dip over or under the expected … if at all. You might be high, or low at different times throughout the day.

A four point saliva test is what’s needed.

I also get cortisol tested when I get my bloods, but it doesn’t really tell me that much because as your question points out, it’s only one point on a 24 hour cycle.

[Clara9 in reply to FallingInReverse]

It's just a blood test in the morning but does it matter what time? 8 or 9am?

[FallingInReverse in reply to Clara9]

The test itself has ranges for each block of time in the day.

[FallingInReverse]

Here’s a quick look of what to expect

Cortisol

[HealthStarDust]

Preferably as close to when you wake as possible.

[JumpJiving]

If you want a NHS GP to pay any attention to the result, make it 9AM. An endocrinologist would likely have more leeway, but GPs (at my practice anyway) will not pay any attention to any cortisol test not done at 9AM.

My local NHS hospital tries to do all cortisol tests and synacthen tests at 9AM also, although the synacthen tests may be more to do with doing the test as soon after the department opens as possible so that patients can take their hydrocortisone or prednisone as soon as possible.

[McPammy]

I’ve had my cortisol checked several times by my NHS endocrinologist. It’s ALWAYS 9am for the highest level according to the NHS.

There are saliva tests available privately and with that test you test yourself 3 times over the course of the day. Cortisol is our circadian rhythm so it goes up and down throughout the day. 9am ish highest. Drops at noon. Then further drop 6pm into the evening to let you sleep for bed time.