Can this one test predict your heart attack risk?
Posted on 11 September 2018
High levels of C-reactive protein could indicate inflammation in your blood vessels, says a Mediclinic physician and rheumatologist.
What is C-reactive protein?
C-reactive protein, or CRP, is produced by the liver and if there is a higher concentration of CRP than usual, it’s a sign of inflammation in your body.
While the test doesn’t indicate exactly where the inflammation is located in your body, it can be an indicator of your risk for developing cardiovascular problems, such as atherosclerosis, which is when plaque builds up inside the walls of your blood vessels.
“Heightened levels of C-reactive protein in the blood can indicate inflammation in the body,” says Professor Helmuth Reuter, physician and rheumatologist at the Winelands Medical Research Centre and Mediclinic Stellenbosch. A simple but crucial blood test can help highlight serious health problems, he says, as these raised levels could point to an infection or a chronic inflammatory condition.
What does the test involve?
It’s a regular blood test. Your blood will be drawn by a medical professional, and your doctor will advise you if you need to fast before the test or not. CRP is often tested for at the same time as a cholesterol test is conducted.
To make sure your test is as accurate as possible, you shouldn’t take the test when you have any kind of infection or inflammation, such as a cold or the flu. Because CRP levels reflect inflammation, the blood level will be very high in these situations.
There are two types of CRP tests – a regular test and a high-sensitivity, also known as an hs-CRP test, which is more common when assessing a patient’s cardiovascular risk. The hs-CRP blood level signals how much low-grade inflammation is present along the blood vessel walls.
How do I know if I need my CRP levels tested?
It depends on what level of risk you are for developing heart disease. Some of the risk factors include high cholesterol, high blood pressure, family history and smoking. If you have heart disease or appear to be at high risk of developing it, it’s unlikely you’ll be sent for a CRP test as you’ll already be on a treatment plan with your doctor. But if you’re at a moderate risk, the CRP test will give your doctor more information to help them pick the right course of action.
What will happen if my test reveals I have high levels of CRP?
Your doctor will explain your results to you, but essentially, in a regular CRP test, the key number is 10. A normal reading for a standard CRP test is less than 10 milligram per litre (mg/L). A test result greater than 10 mg/L is a sign of serious infection, chronic disease or trauma, and will require further testing to determine the cause.
However, when an hs-CRP test is undertaken, the numbers are different. You’re at lower risk if you have an hs-CRP level of less than 2.0 milligram per litre (mg/L), and at higher risk if it’s greater than 2.0 mg/L.
Because CRP is an indicator of inflammation and not heart disease, the test should be conducted twice at an interval of two weeks. A high reading won’t necessarily mean you have heart disease, which is why it’s important to check your cholesterol levels as well for an accurate, all-round risk assessment.