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 infection, the level of procalcitonin in your blood can increase significantly. The test is mostly used if you are seriously ill and your healthcare 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 may help bacterial infections, but not viral infections.

The procalcitonin test is useful in helping to detect sepsis and severe bacterial infections in the early stages and to distinguish between a bacterial infection and other non-bacterial causes of signs and symptoms in a seriously ill person. The test may be used, along with other tests and examinations, to help detect or rule out sepsis in a seriously ill person. It has primarily been used in people who seek care at emergency departments or who are admitted to intensive care units (ICUs) with signs and symptoms that may be due to sepsis.

The procalcitonin test is not considered a replacement for the performance of other laboratory tests. Rather, it provides additional information that may allow appropriate treatment to be initiated or discontinued sooner. The test can also be used to determine the risk that a critically ill person will progress to severe sepsis and septic shock, or the risk of the person dying.

In summary, a procalcitonin test measures the level of procalcitonin in your blood and is used to detect sepsis and severe bacterial infections in the early stages and to distinguish between a bacterial infection and other non-bacterial causes of signs and symptoms in a seriously ill person. The test can also help determine the risk of progression to severe sepsis and septic shock, or the risk of death.