bone profile blood test

[emmjay77]

Hi

I recently had the bone profile blood test which was marked as satisfactory (all levels were within the range).

Yesterday I had a lumbar x ray for severe, sudden onset and ongoing back pain, which turns out to be a trapped nerve.

The x ray also showed a degree of osteoporosis, which I knew nothing about, and I'm confused as to how the blood test was perfectly ok?

Can anyone shed some light on this please?

[Met00]

The bone profile test in the UK is usually just calcium and vitamin D. Calcium blood levels will be normal for most of us, even if our calcium intake is inadequate, because if things are working as they should, blood calcium is prioritised, meaning the bones may lose out. However, an x-ray can only show possible bone thinning, it can't be used to diagnose osteoporosis, so your doctor should request a DEXA scan. If that gives an osteoporosis diagnosis, you should ask your doctor to run blood tests to look for underlying causes: vitamin D, calcium and parathyroid from the same blood draw, thyroid, coeliac and a full blood count.

[yogalibrarian]

The "gold standard" for diagnosing osteoporosis is a DXA which measures bone mineral density (BMD). (There are some newer diagnostic tools using other technologies becoming available.)

DXA is a dual x-ray measurement. "Traditional X-rays used to identify broken bones (for example spine fractures) cannot measure BMD." (IOF)

For osteoporosis to show up on a traditional x-ray there has to be a large loss of BMD.

The "bone profile blood test" measures: calcium, alkaline phosphatase (ALP), albumin, and phosphate in the blood. They do not measure BMD, which is the measure of osteoporosis.

There are other tests of bone turnover markers that might be of more use in diagnosing osteoporosis. But they will only measure bone turnover, not BMD.

To determine if you have osteoporosis, you would need a DXA.

Although a traditional x-ray would not detect osteoporosis until you have lost a large amount of BMD, it will detect osteoarthritis (a totally different condition). A traditional x-ray would also detect osteoporotic fractures. A diagnosis for confirmed fractures would make it easier to get a DXA.

The short answer is the "bone profile blood test" and a DXA are measuring two different things. Low values on the blood test should trigger additional diagnostic tests. But normal values don't rule out osteoporosis.