Performance Evaluation of the Preanalytic Module of the ACL TOP 750 Hemostasis Lab System

High-Speed Centrifugation Fails to Mitigate Severe Lipemic Interference in D-dimer Measurement

OBJECTIVE

To evaluate the impact of varying lipid turbidity (LT) levels on D-dimer measurements after routine centrifugation (RC) and high-speed centrifugation (HC) in lipemic samples.

METHODS

Lipemic samples (triglyceride > 1.7 mmol/L) were classified into four LT grades via HIL testing and visual inspection. Coagulation parameters (APTT, TT, FIB, PT-INR, and D-dimer) were compared between RC (2600 × g/10 min) and HC (10 000 × g/10 min) in 104 lipemic and 30 non-lipemic control samples.

RESULTS

Significant differences (p < 0.05) were observed in all coagulation indices between RC and HC for lipemic samples. LT level was positively correlated with TG and total cholesterol (TC). Deviation rates for APTT, TT, FIB, and PT-INR were below 15%, while D-dimer deviation rates exceeded 50% in severe LT (grades 3-4). D-dimer levels in the lipid layer were significantly higher than those in the plasma layer (p < 0.05). HC failed to resolve interference in severely turbid samples, where D-dimer adhered to chylomicron-rich lipid fractions.

CONCLUSION

Contrary to CLSI recommendations, high-speed centrifugation (HC) significantly reduced D-dimer concentrations in the lower plasma layer of severely turbid specimens (e.g., type II hyperlipidemia), failing to mitigate turbidity interference. This discrepancy may lead to misdiagnosis of high-risk thrombotic conditions, such as pancreatitis. The upper lipid layer, predominantly composed of chylomicrons, exhibits a strong binding affinity with D-dimer, further complicating accurate measurement. Direct dilution, however, may resolve measurement failures in severe LT samples by maintaining analyte integrity while eliminating lipid interference.

Performance testing of four automated coagulation analyzers in a university hospital setting with focus on global coagulation assays

INTRODUCTION

Several automated coagulation analyzers are available for laboratory use. In a university hospital central laboratory, we compared four different instruments. The results for global coagulation assays are presented here.

METHODS

ACL TOP 750 CTS (Instrumentation Laboratory), Atellica COAG 360 (COAG 360), BCS XP (both Siemens Healthineers), and cobas t 711 (Roche Diagnostics) were compared. For inter-instrument comparison, five basic coagulation parameters were analyzed in 476 patient plasma samples. Additional assessments included precision testing using commercial control samples and plasma pools, analysis time for a defined set of samples, sample capacity testing, minimum required sample volumes, and detection quality for hemolytic, icteric, or lipemic (HIL) interferences.

RESULTS

Good concordance between different instruments was evident from Bland-Altman plots and comparison of data from each instrument with the overall median (τ≥0.8). Shortest analysis times were found for BCS XP and COAG 360, COAG 360 revealed highest sample capacity. Observed required sample volumes were broadly in line with manufacturer specifications and varied according to instrument configurations. HIL detection differed between instruments and was best with ACL TOP 750 CTS.

CONCLUSION

The four analyzers showed similarly high levels of concordance, although some variations were apparent. The most significant differences between the instruments were found in analysis times and sample capacity. Analyzer capabilities must be considered when selecting laboratory equipment and defining algorithms for clinical practice.

Clinical Evaluation of the Pre-Analytical Capabilities of Hemostasis Instrument

Objective: Evaluate the technical performance of the pre-analytical hemolysis-icterus-lipemia (HIL) check module on the ACL-TOP-750. Methods: 8433 routine coagulation samples were evaluated for HIL, the presence of clotting and low sample volume by both visual inspection and the pre-analytical HIL check module on the ACL-TOP-750. Results: 7726 samples were in agreement with both methods and 707 were not consistent. 356 samples with low volume were identified by visual inspection and 920 by the instrument (2.7 mL threshold). Visual inspection identified 56 lipemic samples while 13 of those with moderate or high lipemia were identified by the instrument. Visual inspection identified 47 hemolyzed samples while 7 with moderate or high hemolysis were identified by the instrument. Both visual inspection and the instrument identified 36 icteric samples. For triglyceride concentration and bilirubin concentration, there was good correlation between the ACL-TOP-750 and the DXC800 biochemistry analyzer. Among 30 samples with varying amounts of clotting, 27 were discovered by visual inspection and 3 were discovered by the instrument. Conclusion: The pre-analytical check module on the ACL-TOP-750 improved the detection rate of samples below the target 2.7 mL volume, and the accuracy in detection of HIL. However, the automated method could not replace visual assessment of clotting in samples.

Verification of the ACL Top 50 Family (350, 550, and 750) for Harmonization of Routine Coagulation Assays in a Large Network of 60 Laboratories

OBJECTIVES

To verify a single platform of hemostasis instrumentation, the ACL TOP 50 Family, comprising 350, 550, and 750 instruments, across a large network of 60 laboratories.

METHODS

Comparative evaluations of instrument classes (350 vs 550 and 750) were performed using a large battery of test samples for routine coagulation tests, comprising prothrombin time/international normalized ratio, activated partial thromboplastin time (APTT), thrombin time, fibrinogen and D-dimer, and using HemosIL reagents. Comparisons were also made against existing equipment (Diagnostica Stago Satellite, Compact, and STA-R Evolution) and existing reagents to satisfy national accreditation standards. Verification of manufacturer normal reference ranges (NRRs) and generation of an APTT heparin therapeutic range were undertaken.

RESULTS

The three instrument types were verified as a single instrument class, which will permit standardization of methods and NRRs across all instruments (n = 75) to be deployed in 60 laboratories. In particular, ACL TOP 350 test result data were similar to ACL TOP 550 and 750 and showed no to limited bias. All manufacturer NRRs were verified with occasional minor variance.

CONCLUSIONS

This ACL TOP 50 Family (350, 550, and 750) verification will enable harmonization of routine coagulation across all laboratories in the largest public pathology network in Australia.

Coagulation/Complement Activation and Cerebral Hypoperfusion in Relapsing-Remitting Multiple Sclerosis

Introduction

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system with an underlying immune-mediated and inflammatory pathogenesis. Innate immunity, in addition to the adaptive immune system, plays a relevant role in MS pathogenesis. It represents the immediate non-specific defense against infections through the intrinsic effector mechanism “immunothrombosis” linking inflammation and coagulation. Moreover, decreased cerebral blood volume (CBV), cerebral blood flow (CBF), and prolonged mean transit time (MTT) have been widely demonstrated by MRI in MS patients. We hypothesized that coagulation/complement and platelet activation during MS relapse, likely during viral infections, could be related to CBF decrease. Our specific aims are to evaluate whether there are differences in serum/plasma levels of coagulation/complement factors between relapsing-remitting (RR) MS patients (RRMS) in relapse and those in remission and healthy controls as well as to assess whether brain hemodynamic changes detected by MRI occur in relapse compared with remission. This will allow us to correlate coagulation status with perfusion and demographic/clinical features in MS patients.

Materials and Methods

This is a multi-center, prospective, controlled study. RRMS patients (1° group: 30 patients in relapse; 2° group: 30 patients in remission) and age/sex-matched controls (3° group: 30 subjects) will be enrolled in the study. Patients and controls will be tested for either coagulation/complement (C3, C4, C4a, C9, PT, aPTT, fibrinogen, factor II, VIII, and X, D-dimer, antithrombin, protein C, protein S, von-Willebrand factor), soluble markers of endothelial damage (thrombomodulin, Endothelial Protein C Receptor), antiphospholipid antibodies, lupus anticoagulant, complete blood count, viral serological assays, or microRNA microarray. Patients will undergo dynamic susceptibility contrast-enhanced MRI using a 3.0-T scanner to evaluate CBF, CBV, MTT, lesion number, and volume.

Statistical Analysis

ANOVA and unpaired t-tests will be used. The level of significance was set at p ≤ 0.05.

Discussion

Identifying a link between activation of coagulation/complement system and cerebral hypoperfusion could improve the identification of novel molecular and/or imaging biomarkers and targets, leading to the development of new effective therapeutic strategies in MS.

Clinical Trial Registration

Clinicaltrials.gov, identifier NCT04380220.

Pre-analytical quality control in hemostasis laboratories: visual evaluation of hemolysis index alone may cause unnecessary sample rejection

Background

Visual inspection is the most widespread method for evaluating sample hemolysis in hemostasis laboratories. The hemolysis index (HI) was determined visually (visual index, VI) and measured on an ACL TOP 750 (IL Werfen) system with a hemolysis-icterus-lipemia index (HIL) module. These values were compared with those measured on clinical chemistry systems Unicel DXC600 and AU680 and with quantitation of free-hemoglobin (Hb) performed by a spectrophotometric measurement method (SMM).

Methods

The HI was measured in 356 sodium citrate plasma samples, 306 of which were visibly hemolyzed to varying degrees and 50 were not hemolyzed. The analytical performance of each method was evaluated.

Results

Linear regression analysis, calculated between SMM and the other systems in the study, returned coefficients of determination r2 = 0.853 (AU680), r2 = 0.893 (DXC600) and r2 = 0.917 (ACL TOP 750). An r2 = 0.648 was obtained for linear regression analysis between VI and ACL TOP 750. In addition, ACL TOP 750 showed an excellent correlation in multivariate analysis (r2 = 0.958), showing good sensitivity (0.939) and specificity (0.934) and a diagnostic accuracy of 94%. By comparison, DXC600 and AU680 showed coefficients of determination of 0.945 and 0.923, respectively. A cut-off was set at 0.15 g/L free-Hb, as determined by the automated method, such that any hemostasis samples measuring above this threshold should not be analyzed. Based on this criterion, samples were classified as accepted or rejected, and the number of samples discarded during VI or ACL TOP 750 measurements was compared.

Conclusions

This study confirmed that hemostasis laboratories should consider introducing an objective, automated and standardized method to check samples for hemolysis. By relying solely on visual inspection, up to 50% of samples could be unnecessarily rejected. The ACL TOP 750 system demonstrated a satisfactory analytical performance, giving results comparable to those of the reference method.