Procalcitonin, primarily produced in the thyroid gland, is a protein that is transformed to calcitonin, which aids in calcium and phosphorus metabolism. Procalcitonin is greatly increased in severe generalized bacterial infections, and serves as a relatively sensitive marker of sepsis. Normally, procalcitonin levels in the blood are very low to nonexistent due to its fast conversion to calcitonin in the thyroid gland. When severe bacterial, fungal or parasitic infection is present, most cells in the body will produce procalcitonin. Procalcitonin production parallels the severity of infection, therefore higher levels will be seen when infection is more severe. Levels that are decreasing compare closely with effective treatment.
Procalcitonin can aid physicians in the early diagnosis of sepsis, allowing for immediate effective therapy, which saves time and money for the patient. An elevated plasma procalcitonin level can be seen in septic patients with normal or decreased white cell counts, and it has been shown to have greater sensitivity when found in conjunction with elevated C-reactive protein and/or erythrocyte sedimentation rate results. Diseases that will display increased procalcitonin levels are bacteremia (blood infection), bacterial meningitis, lower respiratory infection, pneumonia and systemic inflammatory response syndrome (SIRS). Procalcitonin has also been shown to be elevated in bacterial infections in patients with chronic renal failure and in patients who develop infections post-surgery. Procalcitonin may be particularly helpful in pediatric patients in whom signs of sepsis may be subtle and to differentiate bacterial from viral infection.
Procalcitonin testing is performed on a blood sample drawn from a vein in the patient’s arm. Additional tests may include C-reactive protein, blood culture, CSF cell count and gram stain, antistreptolysin (ASO), erythrocyte sedimentation rate, CBC, sputum culture, and wound culture.
Reference ranges and specimen collection vary from test method and laboratories performing this test. To properly evaluate your test results, consult with the ordering physician or healthcare provider. If you would like to learn more about testing for Procalcitonin click here for further information or you can research one of the references listed below.
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Procalcitonin, Serum. In Mayo Interpretive Handbook .Rochester: Mayo Medical Laboratories (2009).
Revision: Michael Jacewicz, MD. (2009, December). Asceptic Meningitis. Retrieved October 9, 2010, from Merck Manuals Online Library: www.merck.com