A multi-laboratory assessment of congenital thrombophilia assays performed on the ACL TOP 50 family for harmonisation of thrombophilia testing in a large laboratory network

Abstract

Objectives Thrombophilia testing is commonly performed within hemostasis laboratories, and the ACL TOP 50 family of instruments represent a new ‘single platform’ of hemostasis instrumentation. The study objective was to evaluate these instruments and manufacturer reagents for utility of congenital thrombophilia assays. Methods Comparative evaluations of various congenital thrombophilia assays (protein C [PC], protein S [PS], antithrombin [AT], activated protein C resistance [APCR]) using newly installed ACL TOPs 550 and 750 as well as comparative assessments with existing, predominantly STAGO, instrumentation and reagents. Verification of manufacturer assay normal reference ranges (NRRs). Results HemosIL PC and free PS assays showed good comparability with existing Stago methods (R>0.9) and could be considered as verified as fit for purpose. HemosIL AT showed high relative bias with samples from patients on direct anti-Xa agents, compromising utility. Manufacturer NRRs for PC, PS and AT were verified with minor variance. Given the interference with direct anti-Xa agents, an alternate assay (Hyphen) was evaluated for AT, and the NRR also verified. The HemosIL Factor V Leiden (APC Resistance V) evidenced relatively poor performance compared to existing assays, and could not be adopted for use in our network. Conclusions This evaluation of HemosIL reagents on ACL TOP 50 Family instruments identified overall acceptable performance of only two (PC, free PS) of four thrombophilia assays, requiring use of third-party reagents on ACL instruments for the other two assays (AT, APCR).

A multi‐laboratory assessment of lupus anticoagulant assays performed on the ACL TOP 50 family for harmonized testing in a large laboratory network

“…This process is summarized in Figure S1. It should be noted that these evaluations supplement previous evaluations performed and as recently published by our group for routine coagulation tests 14 and congenital thrombophilia testing 15 performed of this instrument platform.…”

“…The LA guidance from CLSI, however, tends to argue against use of the 99th percentile approach, given the multiple steps in the LA process. 7 Some evaluations of ACL TOP instruments have been previously published, as also previously reported by us, 14,15 but none of those previous reports discussed evaluation of LA assays on ACL TOPs, as did none of the cited literature, which was largely focused…”

“…We also confirmed this threeinstrument "equivalence" in a previous evaluation study in relation to routine coagulation assays 14 and also previously assessed the instruments and applicable reagents for congenital thrombophilia tests. 15 The current evaluation also assessed IL methods/instruments/reagents against those already existing at the evaluation sites, but focussed on LA assays. Although primarily done to satisfy ISO 15189 and local National Accreditation standards, findings will also inform on any changes, and how best to advise clinicians who use our service in terms of prior or historical test result comparisons as required.…”

“…More recently, we further reported an evaluation of congenital thrombophilia assays on this platform, using both manufacturer and alternate reagents. 15 The current manuscript reports on a separate evaluation of the ACL TOP 50 family of instruments for LA assay testing in our network, to further enable standardization and harmonization of testing and procedures. We describe an evaluation of an LA assay manufactured by Instrumentation Laboratory (IL; being the manufacturer of the ACL TOP 50 family) and using their dRVVT method, as compared against existing equipment (i.e., Diagnostica Stago or Siemens Instrumentation) and existing dRVVT reagents (Stago) as "reference."…”

“…In this prior evaluation, we essentially confirmed the “equivalence” (or “interchangeability”) of all three TOP instrument types (350, 550, 750) in terms of assay results. More recently, we further reported an evaluation of congenital thrombophilia assays on this platform, using both manufacturer and alternate reagents 15 …”