I'll try to answer as best I can.

I don’t really know why the Endocrinologist ordered the 24-hour urine test.
Here’s my history of the last 7 months.
I had become very tired. Actually, incredibly exhausted. I was on a mission to find out what was wrong. I am in my 60’s. When I was growing up I was very, very ill. I was in Children’s Hospital (for Dr visits, not usually hospital stays) very frequently. In my 30’s I thought it might be useful to get my medical records from them. I got them, never looked at them, threw them in a box.
This last winter, after I had been so tired for so long, I ran across the records in the original folder as they came from Children’s. I started reading them and realized the health answers might be contained in them. The first Dr I showed them to was one of my spinal Dr’s (I have 2 of them plus a surgeon). He was great but that was not his field. I showed them to my GP. She blew me off. I talked about fractures (14 plus – randomly spread out over decades – many were discovered years later in x-rays). She said that was normal childhood stuff (I broke the large bone, lower leg, vertically (up the middle). I told her I was 23 when it happened. “Still childhood”. I dumped her.
I looked for every type of doctor specialty that was contained in those medical records. Endocrinologist was one of them. I found what I thought was a good one and made and appointment. His comment when reading my med records was “this is gold”. He began running lots of tests. (including 24 hour urine test). I have no idea what he was looking for but results began to come in. First significant one was hypogammaglobulinemia. This showed up in a PROTEIN ELECTROPHORESIS, SERUM test.
At the same time, I ended up in Gastroenterology and had a full work up. (I’d been given Pneumovax 23 vaccine (first GP – the one that I fired). The next day my health fell of the table.) Lymphocytic Colitis. First one to actually give a diagnosis was his GI nurse. She’d spent 30 years as an Oncology nurse. She read the test results from Endocrinology as well. (I learned from my medical team that my Lymphocytic Colitis was immune system related.) She gave detailed information about hypogammaglobulinemia. My other doctors had commented, impressed with her detailed write-up.
I talked with the new GP. He dismissed the hypogammaglobulinemia and instead, wanted to do a sleep study. I never went back to him.
I went to an Immunologist. He looked at Endocrinologist’s tests and began testing. He’s a good Immunologist but he wanted me to do a second Pneumovax 23 shot as a test to see if I developed more antibodies the second time around. He proposed a third time as well. I wasn’t comfortable. I waited. I read. I found a very recent NIH study on multiple Pneumovax 23 shots. The results of the study were shocking. The study was so recently released I’m sure my Immunologist had not seen it yet.
I wanted a second opinion.
I contacted Children’s Hospital (same one I’d been to so many times as a child) to get a referral for an Immunologist. I was transferred to the Immunology Department where I was told that Children’s Hospital now accepts adult patients in the fields of Immunology and Heart.
I had to go through a battery of very complex tests to get accepted at Children’s. I passed, or failed, depending on how you look at it. I was accepted.
At this point I’d had so many tests / results that I was having to call the other doctors in my “group” and give them test results so they would have it to help in diagnostics. I asked the clinic (I go to a very large clinic) for a case manager. I was approved – that included a new GP as well.
At this point also, my Endocrinologist diagnosed me with Osteoporosis based on the number (14+ including my back) and type of fractures (my bone density was fine). He prescribed Forteo.
I had my first Children’s Hospital appointment in July. Many more tests. In August I was officially diagnosed with CVID (common variable immunodeficiency). I started antibody treatment last week.
I started Forteo about 10 days ago.

Remember that second GP, the one that wanted to do the sleep study? One thing in his notes, he wrote “This patient self-refers”. I’m honored!