Blood vs urine vs salivary
Blood testing – most hormone experts would agree that blood testing for hormones is superior to urine or salivary testing. This is because blood carries the pool of hormones that will be used to communicate action to cells. Unless hormones are having an action in the place they are produced, they need to be carried through the bloodstream to the target tissues. Even when metabolites are produced, they will still need to travel through the bloodstream to their target tissue if they are of any use in the bodies functioning. One of the problems with testing blood hormone levels is that many hormones bind to a protein which seems to make them inactive, and many blood test will test total (bound + unbound hormone), which doesn’t really tell you hormone activity. You can get around this issue by testing the amount of binding protein and, assuming a certain percentage of binding, can calculate the free level of a hormone. The issue is that labs will not offer this binding protein test for all hormones and, when they do, tend to charge a lot for it. Even though blood is the closest of the three types of testing to the target tissue, it is not a measurement of activity. It is still has to get to the target tissue and target cell, then bind to a receptor to trigger an action. There could be many blocks between the blood and this action. On a side note, frequently a hormone blood panel (a collection of tests for a discounted price) includes Prolactin, a hormone from the pituitary gland. Prolactin is a measure of pituitary health or dopamine levels in the brain and, if high, can indicate blockage of progesterone production in women and testosterone in men.
Urine testing – urine is a collection of waste product that the body is getting rid off. This may or may not reflect blood levels of a hormone. Some hormones, such as progesterone, are only found in urine at a fraction of the level they are found in the blood. This is because the body does not really excrete much progesterone, but only tends to excrete progesterone when it is metabolised to other hormones. On an individual basis this can happen as well (called hypo-excretion) or an individual hormone may be excreted in excess, called hyper-excretion. The problem is we cannot tell if someone is a hypo- or hyper-excretor with only a urine level of that hormone. This means that we could wrongly diagnose a patient as having low or high levels of a hormone if we base it solely on the urine test results. Cortisol is one of the hormones we know can be high on a urine test but low in the bloodstream. The mechanism is not clear, but there seem to be a few reasons, one of them being thyroid dysfunction. Most urine tests for hormones, such as Doctor’s Data’s ‘HuMAP’ test and Precisions Labs ‘Dutch’ test, include 8-OHdG and estrone, tests that are not done in the blood (the estrone testing could be done in the blood but most labs do not do it). Both of these tests are important in order to assess the use of estrogen and its possible increase in, or decrease in, breast and ovarian cancer risk.
Saliva – other than using saliva for cortisol testing, it is not used that often in hormone testing anymore. In most cases hormones do not travel through saliva to get to their target tissues. It is more likely that hormones that are travelling in blood vessels through the salivary glands will spill hormones into the area so they show up in the saliva. There has been some research showing salivary hormone levels fairly accurately reflect blood levels of free hormones but, other than cortisol, the salivary tests are not done frequently enough to confirm consistency of results. This also means that the lab reference ranges are generally too broad to be of much use and optimal ranges are not well established for salivary testing.
In the end, it is important to remember that lab test only give a portion of the information needed to develop an effective treatment. The strength and weaknesses of these various tests need to be understood, and along with experience dealing with these hormones, that effective treatment can be found.