Procalcitonin Test

Urgent safety information

Sepsis is a medical emergency. If you or your loved one has an infection that's not getting better or is getting worse, get medical help right away.

Why this test may be ordered

• To diagnose or rule out a bacterial infection and/or sepsis
• To find out how serious a sepsis infection may be
• To make treatment decisions (such as the need for antibiotics)
• To monitor how well treatment is working
• To diagnose kidney infections in children with urinary tract infections

Preparation and collection

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

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.

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.

Understanding results

Your procalcitonin level is measured in your blood. The following patterns describe what different levels may mean. Your healthcare provider will interpret your result in the context of your overall health and other tests.

• High procalcitonin levels: You most likely have sepsis. You may have a high risk of developing severe sepsis and septic shock, a life-threatening condition when your organs don't get enough blood to work properly. You may have a serious systemic bacterial infection that increases your risk for sepsis. The higher your procalcitonin levels, the higher your risk for sepsis and septic shock. Limitation: 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. Next step: Urgent
• Moderate to mildly high procalcitonin levels: May be a sign of the earlier stages of a systemic bacterial infection, kidney infection (in children only), or conditions other than infections such as tissue damage from trauma, serious burns, recent surgery, or severe heart attack. Limitation: 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. Next step: Prompt
• Slightly high procalcitonin levels: You are unlikely to develop sepsis, but may have a local bacterial infection (such as a urinary tract infection), an infection from another cause (such as a virus), or a systemic bacterial infection that is just beginning. Limitation: 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. Next step: Routine
• Decreasing or low procalcitonin levels (during treatment): If you are being treated for a bacterial infection, decreasing or low procalcitonin levels mean that your treatment is working. Limitation: 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. Next step: Routine

• 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.
• Moderate to mildly high levels may be due to conditions other than infections, such as tissue damage from trauma, serious burns, recent surgery, or severe heart attack.

What to do next

Your healthcare provider will interpret your procalcitonin result along with other tests and your symptoms to guide your care. If you are being treated for a bacterial infection, decreasing or low procalcitonin levels mean that your treatment is working.

• What does my procalcitonin level mean for my condition?
• Do I need any other tests to confirm the cause of my infection?
• How will my procalcitonin level guide my treatment, including the need for antibiotics?

Evidence source

U.S. National Library of Medicine: Procalcitonin Test