Is there blood tests to test my circadian rhythm?

Not yet: Most circadian rhythm testing is based on levels of melatonin in the body. These tests are usually only performed in research laboratories and not in your doctors office. Sometimes questionnaires and a form of sleep wake monitoring called actigraphy is helpful in determining an individuals general circadian rhythm.

Circadian rhythm: There are blood tests that can be done, but we don't use them to determine someone's circadian rhythm. There are hormones that fluctuate predictably with the circadian rhythm, like growth hormone, acth, cortisol and tsh. A good way to "test" your circadian rhythm is your temperature, but the best determinant of your rhythm is your sleep pattern...When you go to bed and sleep and when you wake up.