Validation of the procalcitonin (PCT) assay: Experience in a pediatric hospital

Abstract

ObjectivesProcalcitonin (PCT) is a potential early biomarker used to differentiate sepsis from systemic inflammation. Serial PCT measurement is useful in reducing the duration of antibiotic exposure without increasing treatment failure. Our aim was to establish and evaluate an automated quantitative PCT assay at Texas Children's Hospital. MethodsWe validated the analytical and clinical performance of the automated miniVIDAS B.R.A.H.M.S PCT® assay (BioMerieux®, France) at Texas Children's Hospital. Analytical performance parameters included precision, linearity, accuracy, correlation, and effect of different common interferents (free Hb, bilirubin, triglyceride and rheumatoid factor). Also, the interference of high calcitonin (CT) on PCT assay was tested. We performed clinical correlation of PCT to blood culture, WBC counts and CRP in sepsis patients. ResultsThe PCT assay showed good precision with %CV of <5% for intra-assay and %CV of 6.5% for inter-assay precision. The assay was linear across the measurement range (0.05μg/L–200μg/L). Correlation studies showed a good correlation (r>0.9). No significant effects on PCT levels were seen with common interferents however, calcitonin concentrations of 1000ng/L or more showed cross-reactivity with PCT values. Fourteen (78%) out of the total eighteen patients with positive blood culture, showed median PCT concentrations greater than the cut-off values of 0.15μg/L. ConclusionThe miniVIDAS PCT assay can be used for diagnostic purposes in clinical laboratories. We envision that serial PCT monitoring along with clinical correlation will be beneficial in critically ill patients.