The head of my local CFS support group forwarded this formula to me . . . I had mentioned that I drink water constantly and crave salt on all of my food. I have had several 24 hour urine tests and have more than filled the entire bottle! I used this formula and ALL of my test results were over 10!!!! The highest was 24.3 for me. I have also been using a lot of humidity because I have a chronic sinus infection also . . . Hope this helps! I found it interesting . . . Love, Terri BUN/Creatine ratio as in indicator of hydration. Here's the source and quote: Clinical Anesthesiology, G. Edward Morgan and Maged S. Mikhail, c.1992, published by Appleton & Lange, Chapter 29: Fluid Management and Transfusion, pg.477. "Laboratory signs of dehydration include a rising hematocrit, a progressive metabolic acidosis, a urinary specific gravity greater than 1.010, a urinary sodium less than 20 meq/L, hypernatremia [high blood sodium] and a BUN/creatinine ratio of greater than 10:1." To find your BUN/creatinine level, look on your blood chemistry test results and divide the BUN by the creatinine level. Sometimes it is calculated for you. A result greater than 10 and you are tending toward the dehydrated side. I think the highest I've heard of in our group is 25. There is no prize for the highest number! When you get your blood taken, try to keep a few notes to attach to the results you get later such as (I was fasting, I didn't drink water since night before, I drank water all along, I ate a big salty meal right before, it was very cold and the heat was on, it was hot and I was sweating, it was a good/bad day, etc.) It will help you see patterns in your results. Dehydration is a common situation for many with CFS and/or Orthostatic Intolerance, and becomes a larger problem in certain cicumstatances. For example, in cold weather, the humidity goes down and we lose more moisture through our skin and breath. This is made worse by heating our homes and cars. When one goes through a dysautonomia event from stress or heat or being up and still too long, the body get the message to dump fluids and electrolytes bringing on more deficiencies if don't replenish the liquids AND electrolytes (calcium, magnesium, sodium and potassium).