Procalcitonin

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Also known as: PCT
Formal name: Procalcitonin

At a Glance

Why Get Tested?

To help diagnose sepsis if you are critically ill; to help determine the risk of severe sepsis leading to septic shock; to distinguish bacterial from non-bacterial infections

When to Get Tested?

When you are seriously ill and your health care provider wants to distinguish between sepsis and other causes of the illness; sometimes at intervals to monitor effectiveness of antimicrobial treatment

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

None

The Test Sample

What is being tested?

Procalcitonin is a precursor to the thyroid hormone calcitonin. It is normally produced by special cells in the thyroid gland called C-cells and is present in low levels in the blood. However, it may also be made by other cells in the body when stimulated by an intense stressor, in particular systemic bacterial infection (sepsis; as opposed to local bacterial infections). Other stressors include tissue damage due to events such as trauma, surgery, pancreatitis, burns, cardiogenic shock (related to a heart attack), acute organ transplant rejection, and kidney involvement in urinary tract infections in children.

This test measures the amount of procalcitonin in the blood. Levels of procalcitonin in the blood increase rapidly and significantly when a person has sepsis. They are typically only mildly to moderately elevated when a person has a viral infection, a localized infection, or other illnesses as noted above, which may present with some of the same symptoms as sepsis. This gives the procalcitonin test the potential to be used to help detect the presence of a severe bacterial infection in its early stages and to distinguish between a bacterial infection and other causes of symptoms in a seriously ill person.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

Common Questions

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

Dellinger, R. P. et. al. (2013 February) Surviving Sepsis Campaign: International Guidelines for Management of Severe Sepsis and Septic Shock: 2012. Special Article Critical Care Medicine Journal v 41 (2) [On-line information]. PDF available for download at http://www.sccm.org/Documents/SSC-Guidelines.pdf through http://www.sccm.org. Accessed July 2013.

Lin, J. and Yap, S. L. (Updated 2013 February 11). Procalcitonin. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/2096589-overview through http://emedicine.medscape.com. Accessed July 2013.

(© 1995–2013). Procalcitonin, Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/83169 through http://www.mayomedicallaboratories.com. Accessed July 2013.

Fisher, M. et. al. (Updated 2013 March). Sepsis. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/Sepsis.html?client_ID=LTD through http://www.arupconsult.com. Accessed July 2013.

Jin, M. and Khan, A. (2010). Procalcitonin: Uses in the Clinical Laboratory for the Diagnosis of Sepsis. Medscape Today News from Lab Med v41 (3):173-177. [On-line information]. Available online at http://www.medscape.com/viewarticle/720621 through http://www.medscape.com. Accessed July 2013.

McGee, K. and Baumann, N. (2009 July). Procalcitonin Clinical Utility in Diagnosing Sepsis. Clinical Laboratory News v 35 (7). [On-line information]. Available online at http://www.aacc.org/publications/cln/2009/july/Pages/series0709.aspx# through http://www.aacc.org. Accessed July 2013.

Clarke, W., Editor (© 2011). Contemporary Practice in Clinical Chemistry 2nd Edition: AACC Press, Washington, DC. Pg 519.

Sources Used in Previous Reviews

Yealy, D. et. al. (2009 September 8). Blood Test Narrows Down Need for Antibiotics. MedlinePlus HealthDay News [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/news/fullstory_89106.html through http://www.nlm.nih.gov. Accessed October 2009.

Brown, A. (2009 June 19). Procalcitonin Testing May Shorten Antibiotic Course in ICU Patients. Medscape Today from Reuters Health Information [On-line information]. Available online at http://www.medscape.com/viewarticle/704569 through http://www.medscape.com. Accessed October 2009.

Boggs, W. (2009 January 7). Procalcitonin Levels Lower With Blood Stream Infection in Setting of Prior Sepsis. Medscape Today from Reuters Health Information [On-line information]. Available online at http://www.medscape.com/viewarticle/586453 through http://www.medscape.com. Accessed October 2009.

(2008 December 5). Procalcitonin Discriminates Between Bacterial and Aseptic Meningitis in Children. Medscape Today from Reuters Health Information [On-line information]. Available online at http://www.medscape.com/viewarticle/584813 through http://www.medscape.com. Accessed October 2009.

Barclay, L. (2009 February 9). Procalcitonin, CRP May Predict Serious Bacterial Infection in Febrile Infants. Medscape Medical News [On-line information]. Available online at http://www.medscape.com/viewarticle/588042 through http://www.medscape.com. Accessed October 2009.

Barclay, L. (2009 September 16). Procalcitonin Measurements May Reduce Rates of Antibiotic Use for Lower Respiratory Tract Infections. Medscape Medical News [On-line information]. Available online at http://www.medscape.com/viewarticle/708991 through http://www.medscape.com. Accessed October 2009.

Bennett, N. J. et. al. (Updated 2008 June 26). Bacteremia: Differential Diagnoses & Workup. eMedicine [On-line information]. Available online at http://emedicine.medscape.com/article/961169-diagnosis through http://emedicine.medscape.com. Accessed October 2009.

Lehman, C. (Updated 2009 August). Sepsis in Newborns - Neonatal Sepsis. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/NeonatalSepsis.html?client_ID=LTD through http://www.arupconsult.com. Accessed October 2009.

Lehman, C. et. al. (Updated 2009 August). Pancreatitis, Acute. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/PancreatitisAcute.html?client_ID=LTD# through http://www.arupconsult.com. Accessed October 2009.

Goyal, M. (© 2007). Procalcitonin test could help EPs dx serious bacterial illness faster. Emergency Physicians Monthly [On-line information]. Available online at http://www.epmonthly.com/index.php?option=com_content&task=view&id=263&Itemid=15 through http://www.epmonthly.com. Accessed October 2009.

Carroll, J. et. al. (2007 May 17). Acute Pancreatitis: Diagnosis, Prognosis, and Treatment. American Family Physician [On-line information]. Available online at http://www.aafp.org/afp/20070515/1513.html through http://www.aafp.org. Accessed October 2009.