Original scientific paper

https://doi.org/10.11613/BM.2017.030701

Performance characteristics of lipoprotein-associated phospholipase A2 activity assay on the Dimension Vista analyser and preliminary study of a healthy Italian population

Alessandro De Stefano orcid.org/0000-0002-4379-6868 ; Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, Rome, Italy
Liliana Mannucci orcid.org/0000-0003-2729-9957 ; Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, Rome, Italy
Renato Massoud ; Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, Rome, Italy
Sergio Bernardini ; Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, Rome, Italy
Claudio Cortese orcid.org/0000-0002-9429-5000 ; Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, Rome, Italy

Abstract

Introduction: Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a marker of vascular inflammation associated with coronary heart disease and
stroke. We evaluated analytical performance of the PLAC® Activity Test on Siemens Dimension Vista® 1500 analyzer and measured Lp-PLA2 activity
in Italian adults to establish reference intervals (RIs) and evaluate correlation with circulating lipids and age.
Materials and methods: The evaluation protocol consisted of precision, linearity, sensitivity, method comparison, substrate depletion (“hook”)
effect and interference assessment. Inhibitor (Darapladib) effect was also evaluated. Lp-PLA2 activity was measured in 250 healthy donors (123 males,
127 females, aged 18-70 years). Central 95% RIs were established using nonparametric statistics.
Results: Intra-assay and inter-assay precision showed CVs of 0.6% - 1.4% and 0.9% - 2.0%, respectively. Linearity replicates showed R2 > 0.98.
Limit of quantitation was 5.8 U/L (CV = 9.4%). Bland Altman plot showed bias - 0.9, 95% limits of agreement -6.5 - 4.72. Passing-Bablok regression
showed excellent correlation (Slope = 1.02, 95% CI: 1.01 to 1.03; Intercept = - 1.86, 95% CI: - 3.08 to - 1.26; R2 = 0.999). No “hook effect” was observed
at Lp-PLA2 activities ≤ 1000 U/L. Average Lp-PLA2 activity in 250 healthy donors was 182 ± 44 U/L (mean ± SD). Males showed statistically
significant higher activities than females (P < 0.001). RIs were 107 - 265 U/L for males and 84 - 225 U/L for females. Moderate significant correlation
(r = 0.29, P < 0.001) was found between Lp-PLA2 activity and total cholesterol.
Conclusions: The PLAC® Activity Test shows very good performance characteristics on Dimension Vista® 1500.

Keywords

Lp-PLA2; assay validation; cardiovascular disease; Darapladib; reference intervals

Hrčak ID:

187584

URI

https://hrcak.srce.hr/187584

Publication date:

15.10.2017.

Visits: 1.373 *