Osteoporosis Evaluation

Why are tests done for osteoporosis?

If you have osteoporosis, low bone density, or unexplained bone fractures, tests can determine whether there are any undetected contributing problems, help in the selection of medication for treatment, find out whether you are responding to treatment as expected, or evaluate poor response to treatment.

What tests are usually done?

A 24-hour urine collection can show if there is a problem with intestinal absorption of calcium or leakage of calcium through the kidneys. A fasting blood test is done to evaluate blood chemistries (to see if your calcium or phosphorus level is too high or too low, or if there is a problem with liver or kidney function), blood count (checking for anemia), proteins (to be sure there is no multiple myeloma), vitamin D level (a low level causes trouble with getting calcium to your bones), thyroid function (high thyroid function can cause osteoporosis), antibodies for celiac disease- a condition that may cause poor intestinal absorption of important nutrients, or bone turnover- the rate of bone metabolism (NTX or CTX). X-rays may detect previous fractures of the spine, which can occur with or without back pain and may result in loss of height. Sometimes a nuclear bone scan can identify other kinds of bone disease that cause fractures. In rare cases, a bone biopsy provides helpful information. Other tests may be necessary depending on your particular situation.

How are the tests done?

If a 24-hour urine collection is ordered, please go to the lab to get a container for the urine collection and carefully follow the instructions on this page.
If blood tests are ordered, you must have nothing to eat or drink (except water) after midnight, and be at the lab about 8:00 AM.
If a fasting second-void morning urine specimen is ordered, you must have nothing to eat or drink (except water) after midnight, and be at the lab about 8:00 AM. Urinate at home before you go to the lab, and plan on giving the lab a fresh urine specimen when you are there.

If all three types of tests are ordered, you may combine them in one of the following ways:

  • When you give your 24-hour urine container to the lab at 8:00 AM, you can also have a fasting blood specimen drawn and give them a fresh urine specimen
  • Go to the lab for a fasting blood test and second void urine specimen first, and they will then give you a container for doing the 24-hour urine collection later.

Instructions for 24-Hour Urine Collection

Use the urine collection container that you picked up at the lab. If you normally drink a very large amount of water every day, ask for an extra container if case you completely fill the first one. Plan on beginning the urine collection on a day that is convenient. You must bring the container of urine to the lab for testing the day the collection is completed. Those who work on weekdays may find it easiest to do the collection on a Sunday. For this test to be accurate, you must collect all of the urine produced in 24-hours according to these directions. If your schedule or lifestyle makes it impossible to begin and end the collection at 7:00 AM, then you may select another time, but you must still collect all urine produced for the entire 24-hours. If the lab gives you different instructions than these, we prefer that you follow these or call us with any questions.

  1. Drink the usual amount of liquids, eat your normal diet, and take the usual vitamins, calcium, and medications during the collection period. Do not drink any alcohol during the collection period.
  2. Start the 24-hour period at exactly 7:00 AM by urinating into the toilet to eliminate the urine produced by your kidneys overnight.
  3. Collect all urine produced after 7:00 AM in the container until the following morning.
  4. At 7:00 AM the next morning, complete the collection by emptying your bladder into the container.
  5. During the 24-hour collection period, keep the urine in the refrigerator or on ice. Urine at room temperature may grow bacteria which could spoil the collection.
  6. If you forget to collect any of your urine during the 24-period, you must discard what you have collected, clean and dry the container, and start over.
  7. Label the container with your name, date of birth, date and time of beginning the collection, and the name of the ordering physician.
  8. Deliver the container to the lab with the requisition form as soon as possible after the collection period is complete.