Introduction: Presepsin (soluble CD14 subtype) is a new biomarker of infection and sepsis. Correct interpretation is based on the knowledge of analytical reliability, biological variation, decision limits, and diagnostic effectivity.
Aim: The aim of the study was to verify analytical precision of presepsin measurements, to assess biological variation in healthy subjects, to verify reference and decision limits, to assess diagnostic effectivity, and to compare data with commonly used septic biomarkers - procalcitonin (PCT), CRP and interleukin 6 (IL6).
Material and methods: Analyti-cal precision (repeatability and intermediate precision) was estimated by repeated measurements of commercial control materials. Biological variation was evaluated in a group of 20 healthy volunteers in a 7-week experi-ment. Reference ranges were extracted from the literature and compared with data from healthy subjects.
Results: Precisions of presepsin measurements were 2.0-4.0 % (“within-run”) and 6.1-9.5 % (“between-run”). Intraindividual biological variation of presepsin was 22.3 %, interindividual variation 20.8 %. Index of individuality was 1.07, reference change value (RCV - critical difference) was 72 %. Upper reference limit was around 180 ng/l.
Conclusion: Ana-lytical quality of presepsin measurement is suitable for clinical use. Biological variation parameters enable the use of reference limits, upper reference limit of presepsin is around 180 ng/l. None of the tested biomarkers has universal cut-off value, multiple biomarkers are needed and repeated measurements are advisable.
Keywords: CRP; analytical reliability; decision limits; interindividual biological variation; interleukin 6; intraindividual biological variation; presepsin; procalcitonin; reference limits.