Procalcitonin test FAQ

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

A procalcitonin test measures the level of procalcitonin in your blood. Normally, you have very low levels of procalcitonin in your blood. But if you have a serious bacterial infection , the cells in many parts of your body will release procalcitonin into your bloodstream. A high level of procalcitonin in your blood may be a sign of a serious infection or sepsis  (an overactive and extreme response to infection).

You may need this test if you have symptoms of sepsis or a serious bacterial infection that could become sepsis. Symptoms of sepsis include:

You don't need any special preparation for a procalcitonin test.

High procalcitonin levels mean that you:

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

A procalcitonin test won't show what type of bacteria is causing an infection. To make a full diagnosis, your provider will likely order other tests. But a procalcitonin test does give you important information about your risk for sepsis, so you can start treatment sooner, if needed, and avoid more serious illness.

A procalcitonin test is mostly used if you are seriously ill and your provider thinks you may have a systemic infection (an infection that affects your entire body). The test helps find out whether bacteria or a virus is causing your infection. For example, a procalcitonin test can help tell the difference between bacterial and viral pneumonia . This matters because antibiotics help most bacterial infections, but not viral infections .