Procalcitonin (PCT) in Serum/Plasma
This test measures the level of procalcitonin, a precursor protein made by cells in response to infections, particularly bacterial ones.
["Procalcitonin helps doctors assess the risk of bacterial infection and guide treatment decisions."]
Key facts at a glance
- LOINC
- 13034-4
- Short code
- C peptide sp4 p chal SerPl-mCnc
- Synonyms
- C peptide sp4 p chal SerPl-mCnc
- Category
- coagulation
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0.8
- Ref high
- 1.2
- Critical range
- — – 5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 85610
- SNOMED
- 396252006
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What Is Procalcitonin Used For?
Procalcitonin is primarily used to distinguish between viral and bacterial infections. Higher levels often suggest a bacterial infection, which may require different treatment approaches than viral infections. It can also help monitor how well an infection is responding to treatment.
How Is This Test Performed?
A blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate the serum or plasma, where the procalcitonin levels are measured using a sensitive immunoassay technique.
Why Might You Need This Test?
Your healthcare provider may order this test if you have symptoms of infection, such as fever, chills, or signs of illness. It can also be used in hospitalized patients to help guide decisions about antibiotics or other treatments.
What Are Common Causes of Abnormal Results?
Elevated procalcitonin levels can occur with bacterial infections, severe inflammatory conditions, or exposure to certain medications. Lower levels may be seen in viral infections or when the body is recovering from an infection.
Reference range
INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A
Inform your healthcare provider if you are taking blood thinners. No special preparation required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Procalcitonin is a biomarker that reflects the body’s response to infection. It is particularly useful in differentiating bacterial from viral infections, helping clinicians tailor treatment more precisely. However, it is not definitive on its own and should be interpreted alongside clinical findings and other diagnostic tests.
Short name
PCT
Frequently asked questions
What does a high procalcitonin level mean?
Can procalcitonin levels change over time?
Is there any preparation needed before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy