Procalcitonin Test
Reviewed
Also called: PCT test, Procalcitonin
A procalcitonin test measures the level of procalcitonin in your blood. Normally, you have very low levels of procalcitonin in your blood.
Specimen: blood
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. 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
If a result or symptoms suggest an emergency, get emergency medical help right away.
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).
- High procalcitonin levels: High procalcitonin levels mean that you: most likely have sepsis, 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, may have a serious systemic bacterial infection that increases your risk for sepsis Limitation: The higher your procalcitonin levels, the higher your risk for sepsis and septic shock. Next step: If you or your loved one has an infection that's not getting better or is getting worse, get medical help right away.
- Moderate to mildly high procalcitonin levels: Moderate to mildly high levels of procalcitonin may be sign of: the earlier stages of a systemic bacterial infection, kidney infection, in children only, conditions other than infections, such as tissue damage from trauma, serious burns, recent surgery, severe heart attack Limitation: A procalcitonin test won't show what type of bacteria is causing an infection. Next step: To make a full diagnosis, your provider will likely order other tests.
- Slightly high procalcitonin levels: Slightly high levels of procalcitonin mean that you are unlikely to develop sepsis, but they may be a sign of: a local bacterial infection, such as a urinary tract infection, an infection from another cause, such as a virus, a systemic bacterial infection that is just beginning Limitation: A procalcitonin test won't show what type of bacteria is causing an infection. Next step: To make a full diagnosis, your provider will likely order other tests.
- 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: Normally, you have very low levels of procalcitonin in your blood. Next step: If you or your loved one has an infection that's not getting better or is getting worse, get medical help right away.
- 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
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.
- 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
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.