The TSH test involves simply drawing some blood from your body. The blood will then be analyzed in a lab.
It’s best to do this in the morning as your TSH levels can fluctuate throughout the day. No preparation is needed (such as overnight fasting). However, if you’re on certain medications, like dopamine and lithium, you may need to come off them beforehand. Check with your doctor to find out. You shouldn’t feel any pain beyond a small prick from the needle in your arm. You may have some slight bruising too.