Serum procalcitonin measurement is used to diagnose bacteremia and sepsis in adults and children, to diagnose renal involvement in urinary tract infections in children, to diagnose bacterial infections in neutropenic patients, to diagnose risk and septic shock monitoring, for the diagnosis of systemic secondary infections after surgery and in severe traumas, burns and multi-organ failure, for differential diagnosis microbial from viral meningitis, the differential diagnosis of bacterial from viral pneumonia and to monitor therapeutic response to antimicrobial therapy.
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Procalcitonin (PCT, ProCT) is a 116 amino acid protein precursor form of calcitonin. It is produced and secreted by the thyroid gland and is typically undetectable in the blood of healthy individuals. In response to infection and systemic inflammation, the secretion of procalcitonin in the bloodstream increases, and in combination with proteolytic enzymes, it breaks down to the active hormone calcitonin. After an infection develops, procalcitonin rises within 3 hours, peaks within 12-24 hours, and has a half-life of 22-29 hours.
When a bacterial infection causes inflammation, procalcitonin is particularly pronounced because it is also released by the liver, kidneys, lungs, muscles, and adipose tissue, elevating procalcitonin levels in serum significantly above normal levels. Thus, procalcitonin measurement helps differentiate bacterial infections from other pathological conditions and is a more sensitive and specific marker for this purpose than C-reactive protein (CRP). For example, procalcitonin measurement helps differentiate lower respiratory bacterial infections from other conditions. Procalcitonin is also associated with the severity of the disease and is helpful for the detection of severe microbial infections in children.
Monitoring serum procalcitonin values may be particularly useful in monitoring response to antibiotic therapy.
Possible Interpretations of Pathological Values
- Procalcitonin < 0.50 ng/mL. Infection is not excluded since local inflammation can be associated with such values.
- Procalcitonin > 2.0 ng/mL. Indicative of systemic bacterial infection or severe localized inflammation. It may also be related to trauma, burns, polyorganic deficiency, etc.
- Procalcitonin > 10.0 ng/mL. Indicative of sepsis
Important Note
Laboratory test results are the most critical parameter for diagnosing and monitoring all pathological conditions. Between 70 to 80% of diagnostic decisions are based on laboratory tests. Correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased."
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be analyzed based on each case and family history, clinical findings, and other laboratory tests and information. Your physician should explain the importance of your test results.
At Diagnostiki Athinon, we answer any questions you may have about the test you perform in our laboratory and contact your doctor to ensure you receive the best possible medical care.
