Osteoporosis screen (Bone markers) at Cheltenham Hospital

What is a bone markers test?

A bone markers test is a blood or urine test that measures substances released as your bone naturally breaks down and rebuilds itself, a process called bone turnover. It's important to know that this test is not used to diagnose osteoporosis or to work out your risk of breaking a bone; it's mainly used alongside other tests and results to help monitor how well an osteoporosis treatment is working.

Why might I need one?

Bone marker tests are sometimes used to help evaluate conditions affecting bone, such as osteoporosis, Paget's disease (a condition causing enlarged, weakened bones), or cancer that has spread to the bone.

Most often, though, they're used to monitor people who already have a diagnosed bone condition and are having treatment for it, to see how well their body is responding.

Bone markers are mainly used in specialist centres, and many people having osteoporosis treatment won't need this test at all, since there are other ways for your doctor to check whether treatment is working, such as whether you've broken a bone or the results of a bone density (DEXA) scan.

An osteoporosis specialist may refer you for a bone marker test if they feel it would add useful information in your particular case.

What are the benefits of having it?

A bone markers test is a non-invasive way of assessing bone turnover. Because a bone density (DEXA) scan usually can't be usefully repeated more often than every couple of years, bone markers can show whether a treatment is having an effect much sooner, sometimes within just a few months. This means your specialist can consider adjusting your treatment sooner if it isn't working as expected.

Are there different types of the test?

Bone marker tests fall into two broad categories:

• bone resorption markers, which reflect the breakdown of old bone, such as CTX (C-terminal telopeptide); these can be measured in blood or urine
• bone formation markers, which reflect the building of new bone, such as P1NP (procollagen type 1 N propeptide); these are measured in blood.

Your doctor will decide which specific marker or markers are most useful for your situation.

How do I prepare for the test?

Bone turnover naturally follows a daily pattern: it's highest first thing in the morning and decreases by lunchtime, and eating a meal can lower marker levels too. For the most accurate and comparable result, you'll usually be asked to:

• have your blood sample taken while fasting, first thing in the morning
• if you're providing a urine sample, use your second sample of the morning, while still fasting
• have any repeat tests done at the same time of day, and ideally at the same laboratory, to keep results comparable.

What happens during the test?

Depending on which specific marker your doctor wants to check, you'll either have a small blood sample taken from a vein in your arm, or you'll be asked to provide a urine sample. This is a straightforward test and doesn't involve any special procedure beyond the sample being taken under the preparation conditions above.

What happens after the test?

If you're being monitored during osteoporosis treatment, your specialist will look for a meaningful change in your results over time, usually checking again a few months after you start or change treatment, rather than relying on a single reading.

Bone marker results can be difficult to interpret on their own, since many things, including food, the time of day, and the medicines you're taking, can affect them. It's important that a specialist familiar with these tests reviews your results alongside your wider clinical picture.

What are the risks or side effects?

A bone markers test is a standard blood or urine test, so it carries very little risk beyond the usual, brief discomfort or minor bruising that can happen with any blood draw.

The main thing to be aware of is that results can be affected by several factors and aren't always straightforward to interpret. An unusually high result isn't necessarily typical of common osteoporosis and may prompt your specialist to look into other possible causes.