Comparison of Revvity soluble fms-like tyrosine kinase-1 and Placental Growth Factor methods on the DELFIA Xpress with Roche methods on the cobas e411: in a patient cohort with suspected preeclampsia as defined by NICE

Background: Measurement of angiogenic biomarkers; soluble fms-like tyrosine kinase-1 (sFlt-1) and placental like growth factor (PlGF), are increasingly used to support the diagnosis of preeclampsia in routine clinical practice. There are an increasing number of methods available for the analysis of these markers but data showing the comparability of their analytical performance is limited. Methods: The methods for sFlt-1 and PlGF from Revvity were evaluated and compared against the more widely used Roche methods. Imprecision studies and paired comparisons studies were undertaken and data evaluated for numeric agreement and clinical concordance relative to manufacturer recommended threshold for risk stratification for preeclampsia. Results: Preeclampsia prevalence in the study population tested was 17.6%. Imprecision estimates (CV%) for Revvity sFlt-1 and PlGF methods calculated from quality control material were between 4.7 and 9.6% and 8.1 to 13.4% for the calculated ratio. Precision profiles derived from 582 clinical specimens analysed in duplicate had a median CV% for PlGF of 1.6%, IQR 2.2%; for sFlt-1 a median CV% of 1.1%, IQR 1.6%; and for the ratio a median CV% of 2.0%, IQR 2.5%. Comparison against the Roche PlGF and sFlt-1 methods in 437 clinical specimens showed an overall Passing-Bablok regression relationship for PlGF of y = -23.4 + 0.73x (r=0.983) and for sFlt-1, y = -87.7 + 0.40x (r=0.971). However, there was notable concentration dependant bias for both assays. Concordance of the sFlt-1/PlGF ratio relative to manufacturer specific rule-in and rule-out thresholds was 95.2%. Conclusions: The Revvity methods show a concentration dependent negative bias compared to the Roche methods. Risk stratification for discordant ratio results were always lower for Revvity, missing PE within 28 days for 11 patients in this study. Further work is required to understand the differences observed between methods, particularly the calibration strategy, and specificity relative to different isoforms.

Grantor dc:publisher

Oxford Brookes University

Author dc:creator

• Marr, Rhiannon

Contributors dc:contributor

• Brooks, Susan
• James, Tim

Statement dc:rights

• All rights reserved

Language dc:language

en

DOI dc:identifier

https://doi.org/10.24384/59y3-8k81

OAI identifier oai:identifier

tle:603edf3a-d21f-4c01-b2fb-f7d781b81da0:d6bd9758-527a-46cd-bfe2-c433766e8fca:1