Is a peptidde precursor of the hormone calcitonin, the latter being involved with calcium homeostasis. The level of procalcitonin rises in response to a pro-inflammatory stiumulus, including those of a bacterial origin.
Procalcitonin has been extensively studied and has been shown to be a useful biomarker for bacterial infections related to PNA and sepsis. It is not recommended as a biomarker in other infections.
Interpretation of procalcitonin results should always be perfrormed in conjunction with evaluation of signs and symptoms that may suggest the presence of bacterial infection, as well as diseases and conditions that may account for a patient's apparent systemic infalmmatory response.
A baseline procalcitonin level should be drawn for suspected lower respiratory tract infections and sepsis infections. Repeat levels should be drawn 12 hrs after baseline for sepsis and daily for PNA.
A reduction of 80% or more from baseline, or a level below 0.5 ng/ml suggests a positive response that should prompt reevaluation and consideration for a reduction or de-escalation in antimicrobial therapy.
A normal procalcitonin level is < 0.1 ng/ml (in infants >72 hours and adults)
Suspected Lower Respiratory Tract Infection