At a Glance
Why Get Tested?
To help diagnose sepsis in a person who is critically ill; to help determine the risk of severe sepsis leading to septic shock in a person who has sepsis; to distinguish bacterial from non-bacterial infections
When to Get Tested?
When someone is seriously ill and a doctor wants to distinguish between sepsis and other causes of the illness; to help guide treatment in a patient with sepsis
A blood sample drawn from a vein in your arm
Test Preparation Needed?
The Test Sample
What is being tested?
This test measures the amount of procalcitonin in the blood. 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 infection from other causes, tissue damage due to events such as trauma, surgery, pancreatitis, burns, cardiogenic shock – related to a heart attack – and acute organ transplant rejection.
Levels of procalcitonin in the blood increase rapidly and significantly when a person has sepsis. They are not as markedly elevated when a person has a viral infection or other illnesses, as noted above, which may present with 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 another cause of a seriously ill person's symptoms.
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.
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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.
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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.
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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.