So Vitamin D and Calcium and PTH and all kinds of things I do not understand. BUT, there is a Dr. Norman who KIND OF makes it easy and might even keep you from having unnecessary surgery to remove a tumor that isn't there. The website goes on forevermore. The most critical parts, for ME are below. This is to help doctors who may not know much about the thyroid (and even less about wls) interpret test results. I have been known to print this out and take it to my doctor. http://www.parathyroid.com/hyperparathyroidism-diagnosis.htm It's best to read it all...several times...but then scroll down to this part: High Parathyroid Hormone Levels in Patients with Intestinal Absorption Problems, Such as: Gastric Bypass Surgery, and Celiac Sprue, and Crohn's Disease. And study the graphic that is in that section because IT IS ABOUT YOU!!! High Parathyroid Hormone Levels in Patients with Intestinal Absorption Problems, Such as: Gastric Bypass Surgery, and Celiac Sprue, and Crohn's Disease. There is a growing group of patients who have dramatic life-long problems absorbing calcium in their diet. These patients are now illustrated on our graph in the purple area. These patients have a problem with their intestines that prevent them from absorbing calcium well. Since they don't (can't) absorb calcium from their diet, their NORMAL parathyroid glands will do what they are supposed to do... maintain a proper calcium level in the blood. There is only one thing these normal parathyroid glands can do... all four glands enlarge and produce lots of PTH which removes calcium from the bones--its the only place to get the calcium. The blood calcium is therefore maintained appropriately in the normal range (usually low normal between 8.2 and 9.2, but can be as low as 7.0) at the expense of taking calcium out of the bones. Thus these patients have very significant osteoporosis, high PTH levels, low normal calcium and high alkaline-phosphatase (shows increased bone destruction). These patients do NOT need their parathyroid glands removed. They have developed a total-body calcium deficit due to a longstanding inability to absorb calcium through their intestines. The most common people in this purple group are 1) those who have had gastric bypass surgery for weight loss, 2) those with Celiac Sprue, 3) those with Crohn's disease, and 4) those who have had a significant part of their intestines surgically removed. Patients who have had gastric bypass surgery will eat food which then is routed around most of their stomach and the first part of their intestines (thus the term 'bypass'). Virtually 100% of these patients will have malabsorption of calcium. Thus, all patients who undergo gastric bypass for weight loss must be taking calcium and vitamin D every day or they will develop a total body calcium deficit which leads to overproduction of PTH by normal parathyroid glands leading to severe osteoporosis and the problems described here. Do NOT remove these NORMAL functioning parathyroid glands even though they are making lots of PTH... they are doing so appropriately. The treatment for these patients is to fix their calcium deficit by giving them daily calcium and Vit D pills. Note that patients who have the new gastric banding do not have this problem since they do not get their stomach and first part of their intestines bypassed. Also note that it does occasionally occur that a person has a true parathyroid adenoma and has had their stomach bypassed... But, you will typically see that these patients had high calcium PRIOR to their stomach bypass. Celiac Sprue is a disease of the intestines that inhibits patients from absorbing certain types of foods, including calcium. Like the patients with gastric bypass, their poor ability to absorb calcium leads to a total-body calcium deficit over a period of many years. They all must be on some form of calcium and Vitamin D or they will develop severe osteoporosis as their normal parathyroid glands destroy their bones to keep the calcium in the blood in the normal range for the brain. DO NOT remove the parathyroid glands in a patient with celiac sprue. If you are not sure of the diagnosis, send them to a gastroenterologist who can biopsy the mucosa of the intestines and do a very specific test. Crohn's disease is a disease of the intestinal lining and these patients cannot absorb calcium (and vitamin B-12) very well. Unfortunately, some of these patients also have had some of their intestines surgically removed, and they can ge very high PTH levels as their NORMAL parathyroid glands work hard to try to maintain the calcium in the normal range... they get the calcium from the only place they can--the patient's bones.