A comparison study of routine coagulation screening tests (PT and APTT) by three automated coagulation analyzers

Abstract

Background: In recent times, growing coagulation test volume and constricted personnel budgets have enhanced interest in automated coagulation analyzers. Objective: (i) To compare the reliability of routine coagulation test [prothrombin time (PT) and activated partial thromboplastin time (APTT)] using mechanical, photo-optical, and nephelemetric methods by three automated coagulation analyzers. (ii) To evaluate the performance of a newly installed fully automatic coagulation analyzer [STA Compact Max (Stago)] and compare the consistency of its testing results with the confirmed clinical automatic coagulation analyzer at our department (Sysmex and ACL Top). Materials and Methods: Trisodium citrated (3.2%) 60 blood samples, which came to special (coagulation) laboratory with request of PT and APTT (with or without anticoagulant, abnormal, and normal/controls), Transfusion Medicine and Immunohematology Department, Christian Medical College, Vellore, Tamil Nadu, India, were included into study randomly. Sample were run on Sysmex CS2000i (Sysmex Corporation, Japan), photo-optical clot detection; ACL Top (Instrumentation Laboratory, USA), nephelometry clot detection method; and STA Compact Max (Stago, USA), viscosity-based (mechanical) clot detection. Result: Correlation was determined using Bland and Altman analysis, which demonstrated a good agreement between Sysmex CS2000i, ACL Top, and STA Compact Max for PT and APTT. A total of 10 samples (16.7%) with visually observed interferences were identified and tested on all three analyzers and showed good agreement with optical and mechanical methods. Conclusion: This study showed good agreement between newly installed STA Compact Max based on mechanical endpoint detection method with already standardized Sysmex CS 2000i and ACL Top, which work on photo-optical endpoint detection method, for evaluation of screening coagulation tests such as PT and APTT even in case of variables such as partially lysed/icteric samples. Three automated analyzers can be used interchangeably.