Clinical Usefulness of Procalcitonin in Febrile Patients ; Comparison with Erythrocyte Sedimentation Rate and C-Reactive Protein

Kim, Sang Il; Shim, Byoung Yong; You, Hyei Young; Jung, Jung; Wie, Seong Heon; Kim, Yang Ree; Kang, Moon Won

Abstract

BACKGROUND
Procalcitonin (PCT) is a propeptide of calcitonin which is found in elevated concentration in the serum during systemic bacterial, fungal or protozoal infection. To evaluate clinical value of PCT for early differential diagnosis of causes in febrile patients, its levels were serially measured and compared with erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP).
METHODS
Thirty-six patients meeting criteria for the systemic inflammatory response syndrome with fever were allocated into four groups. Sera were collected to measure PCT (immunoluminometric assay), ESR (Westergren method) and CRP (nephelometry) at the onset of fever and twice thereafter at 48 hours intervals. Group I included nineteen patients with bacterial infection who were diagnosed as acute pyelonephritis (n=7), sepsis (n=6), pneumonia (n=2), soft tissue infection (n=3) and infective endocarditis (n=1). Group II included patients diagnosed as viral meningitis (n=2), chickenpox (n=1), cryptococcal meningitis (n=1), and tuberculosis (n=4). Group III included four patients with malaria. Group IV included non-infectious febrile patients diagnosed as adult onset Still's disease (n=2), Kikuchi's disease (n=2) and drug fever (n=1).
RESULTS
Patients in group I (median 1.34 ng/mL) and III (2.41 ng/mL) had markedly elevated serum PCT concentrations at the onset of fever, whereas patients in group II (0.20 ng/mL) and IV (0.11 ng/mL) had normal range PCT levels at the onset of fever (P<0.01). All the groups had elevated ESR and CRP levels at the onset of fever. After 48 hours and 96 hours, in patients group I and III, elevated PCT levels were declined with time course (P<0.05). But all the measured ESR and CRP levels had not changed significantly (ESR; P=0.89, CRP; P=0.23).
CONCLUSION
Procalcitonin is a more useful serum marker than ESR and CRP for initial differential diagnosis of febrile systemic inflammatory response syndrome. It also provide patient's information earlier than ESR and CRP in febrile patients with bacterial infection and malaria.