Biological variation of proprotein convertase subtilisin/kexin type 9 (PCSK9) in human serum

• Published in: Clinica chimica acta Vol. 521; pp. 59 - 63
• Main Authors: Jabor, Antonín, Vacková, Tereza, Kubíček, Zdenek, Komrsková, Jitka, Protuš, Marek, Franeková, Janka
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.10.2021
• Subjects: Biological variation; Cholesterol, LDL; Humans; Index of individuality; Proprotein Convertase 9; Proprotein convertase subtilisin/kexin type 9 (PCSK9); Receptors, LDL; Reference change value; Subtilisins; II; RCV; Proprotein convertase subtilisin/kexin type 9 (PCSK9); Reference change value; Index of individuality; PCSK9; CVA; PCSK9-i; Biological variation; CV; CVG; CVI; RI
• ISSN: 0009-8981; 1873-3492; 1873-3492
• DOI: 10.1016/j.cca.2021.06.023

•Within-subject biological variation of PCSK9 in human serum was 23.2%, between-subject biological variation was 10.9%.•Index of individuality was 2.13, thus enabling the use of reference intervals.•Reference change value was 66.3%.•The estimation of homeostatic point can be based on at least 3 blood samples to assess its value within ±25%. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is involved in the regulation of LDL receptors. Inhibition of PCSK9 increase uptake of LDL-particles and pathogen-associated molecular patterns (PAMPs). The aim of our study was to evaluate biological variation of serum PCSK9. Within-subject (CVI) and between-subject (CVG) biological variations were assessed in 14 healthy volunteers in a 6-week protocol (7 samples, equidistant time intervals). Serum concentration of PCSK9 was measured by a Quantikine ELISA assay (R&D systems, Bio-Techne Ltd., UK) on a DS2 ELISA reader (Dynex Technologies GmbH, Germany). Precision (CVA) was assessed by duplicate measurements. Two methods with different levels of robustness were used for the estimation of CVI, SD-ANOVA and CV-ANOVA method. We calculated the index of individuality and reference change values. The experiment was fully compliant with EFLM database checklist. The within-subject values of PCSK9 in healthy persons, as calculated by two statistical methods, were 23.2% (SD-ANOVA with CVA of 5.6%) and 26.6% (CV-ANOVA with CVA of 4.8%). The CVG was 10.9% (SD-ANOVA), index of individuality and RCV were 2.13 and 66.3%, respectively. The high index of individuality indicates that common reference intervals can be used to interpret serum PSCK9 values.