PB1103 - Clinical performance evaluation of the new Stago systems for APTT determination: sthemO PTTA and sthemO CK Prest on sthemO 301 analyzer.

Background: Activated partial thromboplastin time (aPTT) assays are essentials in the routine hemostasis test panel to explore the intrinsic and common coagulation pathways. To face future challenges and to ensure proper patient medical care continuity, a new Medium-high throughput analyzer, sthemO 301 was developed with dedicated reagents.

Aims: To prove the clinical performances of sthemO PTTA and sthemO CK Prest reagents on sthemO 301 by demonstrating their substantial equivalence versus STA®- PTT A or STA®-C.K. Prest on a STA-R® Max in seconds and ratio units.

Methods: 351 samples were included on three sites for sthemO PTTA and 330 for sthemO CK Prest from normal individuals, patients anticoagulated with unfractionated, low molecular weight heparins or direct oral anticoagulants, patients with lupus anticoagulant, with intrinsic factor deficiencies, with liver failure or with Disseminated Intravascular Coagulation. Samples spiked with heparin were also tested in order to cover the measuring ranges. Ratio were calculated thanks to a local mean normal time (MNT) determined by each site on each system with about 20 fresh healthy subjects’ samples.

Results: The sthemO PTTA MNT for GHBS, Cerba and Medibio were respectively 33.8 sec, 32.7 sec and 34.2 sec while the STA®- PTT A MNT were 33.2 sec, 33.3 sec and 33.9 sec.
The sthemO CK Prest MNT were respectively 28.1 sec, 28.0 sec and 28.0 sec while the STA®-CK Prest MNT were 28.6 sec, 29.1 sec and 28.7 sec.
Passing-Bablok was performed to evaluate the correlation by pooling results of all sites. Refer to Table and Figure.

Conclusion(s): sthemO PTTA and sthemO CK Prest on sthemO 301 comparison to STA® - PTT A and STA® - C.K. Prest on STA-R® Max met all criteria for results expressed in seconds and ratio. The consistency of results between the two system prove their substantial equivalence. Therefore, the intended purpose of these reagents is validated.