Recent advances in laboratory hematology reflected by a decade of CCLM publications

On the occasion of the 60th anniversary of Clinical Chemistry and Laboratory Medicine (CCLM) we present a review of recent developments in the discipline of laboratory hematology as these are reflected by papers published in CCLM in the period 2012–2022. Since data on CCLM publications from 1963 to 2012 are also available, we were able to make a comparison between the two periods. This interestingly revealed that the share of laboratory hematology papers has steadily increased and reached now 16% of all papers published in CCLM. It also became evident that blood coagulation and fibrinolysis, erythrocytes, platelets and instrument and method evaluation constituted the ‘hottest’ topics with regard to number of publications. Some traditional, characteristic CCLM categories like reference intervals, standardization and harmonization, were more stable and probably will remain so in the future. With the advent of important newer topics, like new coagulation assays and drugs and cell population data generated by hematology analyzers, laboratory hematology is anticipated to remain a significant discipline in CCLM publications.

International multicenter, multiplatform study to validate Taipan snake venom time as a lupus anticoagulant screening test with ecarin time as the confirmatory test: Communication from the ISTH SSC Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibodies

BACKGROUND

Lupus anticoagulant (LA) assays are compromised in anticoagulated patients, and existing strategies to overcome the interferences have limitations. The prothrombin-activating Taipan snake venom time (TSVT) screening test and ecarin time (ET) confirmatory test are innately insensitive to vitamin K antagonists (VKA) and direct factor Xa inhibitors (DFXaI).

OBJECTIVES

Validate standardized TSVT/ET reagents for LA detection, in a multicenter, multiplatform study.

PATIENTS/METHODS

Six centers from four countries analyzed samples with TSVT/ET from 81 nonanticoagulated patients with LA, patients with established antiphospholipid syndrome (APS), and proven persistent LA who were either not anticoagulated (n = 120) or were anticoagulated with VKAs (n = 180) or DFXaIs (n = 71). Additionally, 339 nonanticoagulated LA-negative patients, and 575 anticoagulated non-APS patients (172 VKA, 403 DFXaI) were tested. Anticoagulant spiking experiments were performed and 112 samples containing potential interferences (i.e., direct thrombin inhibitors) were tested. Results were evaluated against locally derived cutoffs. Imprecision was evaluated.

RESULTS

Cutoffs were remarkably similar despite use of different analyzers and donor populations. Cutoffs for TSVT ratio, ET ratio, percent correction, and normalized TSVT ratio/ET ratio ranged between 1.08 and 1.10, 1.09 and 1.12, 9.3% and 14.8%, and 1.10 and 1.15, respectively. Coefficients of variation for TSVT and ET ratios were ≤5.0%. TSVT/ET exhibited sensitivity, specificity, and negative and positive predictive values of 78.2%/95.0%/86.3%/91.5%, respectively, with established APS as the LA-positive population, and 86.9%/95.0%/76.8%/97.4%, respectively, with triple-positive APS. Interference was seen with direct thrombin inhibitors, unfractionated heparin, and low molecular weight heparins, but not VKAs or DFXaIs.

CONCLUSIONS

TSVT/ET are validated for LA detection in nonanticoagulated patients and those on VKAs or DFXaIs.

Comparability of sample results and commutability of reference materials among different measurement procedures for protein C activity assays

BACKGROUND AND AIMS

Several types of measurement procedures (MPs) for protein C activity assays are currently available. Clinical sample (CS) results among different MPs should be comparable. The commutability of reference materials (RMs) is an essential requirement to achieve comparability of CS results.

MATERIALS AND METHODS

Considering the total error calculated using reliable biological variation (BV) data and external quality assessment (EQA) criteria, we chose the allowable limits of comparability and criterion of commutability. According to Clinical and Laboratory Standardization Institute EP9 and our previous studies, 92 CSs were used to evaluate the comparability among the three MPs (Sysmex CS-5100, IL ACL TOP 700, and STA-R Evolution). The difference in bias method recommended by International Federation of Clinical Chemistry and Laboratory Medicine was used to assess the commutability of six RMs, including World Health Organization (WHO) IS 02/342.

RESULTS

The compliance rates of CSs were 94.6-100% with the corresponding calibration mode. WHO IS, HemosIL calibration plasma, and candidate RMs, PC20201 and PC20202, were commutable between each pair of the three MPs.

CONCLUSION

It is feasible to set the allowable limits of comparability and the criterion of commutability based on the BV and EQA criteria.

Prevalence and Clinical Impact of Reduced Coagulation Factor XII Activity in Patients Receiving Extracorporeal Membrane Oxygenation

OBJECTIVES

Extracorporeal membrane oxygenation provides large surface exposure to human blood leading to coagulation activation. Only limited clinical data are available on contact activation and coagulation factor XII activity in extracorporeal membrane oxygenation patients.

DESIGN

Prospective cohort study.

SETTING

Three medical ICUs at the Medical University of Vienna.

PATIENTS

Adult patients receiving venovenous or venoarterial extracorporeal membrane oxygenation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the change in coagulation factor XII activity in response to extracorporeal membrane oxygenation. Secondary outcomes included the prevalence of reduced coagulation factor XII activity (< 60%) among patients receiving extracorporeal membrane oxygenation and association of coagulation factor XII activity with thromboembolic and bleeding complications. An exploratory endpoint was the association of coagulation factor XII activity and activated partial thromboplastin time in heparinase-treated samples in vitro. Fifty-one patients with a total of 117 samples were included in the study between July 2018 and February 2020. Fifty patients (98%) had reduced coagulation factor XII activity at any timepoint during extracorporeal membrane oxygenation. Median coagulation factor XII activity during extracorporeal membrane oxygenation treatment was 30% (interquartile range, 21.5-41%) and increased after discontinuation (p = 0.047). Patients with thromboembolic complications had higher median coagulation factor XII activity during extracorporeal membrane oxygenation (34% vs 23%; p = 0.023). The odds of a thromboembolic event increased by 200% per tertile of median coagulation factor XII activity (crude odds ratio, 3.034; 95% CI, 1.21-7.63). No association with bleeding was observed. In heparinase-treated samples, coagulation factor XII activity correlated well with activated partial thromboplastin time (r = -0.789; p = 0.007).

CONCLUSIONS

We observed a high prevalence of reduced coagulation factor XII activity in adult patients on extracorporeal membrane oxygenation, which may confound activated partial thromboplastin time measurements and limit its clinical usefulness for monitoring and titrating anticoagulation with unfractionated heparin. Lower coagulation factor XII activity was associated with less thromboembolic complications, which may highlight the potential of coagulation factor XII to serve as a target for anticoagulation in extracorporeal membrane oxygenation.

A comparative evaluation of the CN‐6000 haemostasis analyser using coagulation, amidolytic, immuno‐turbidometric and light transmission aggregometry assays

Background

The CN‐6000 (Sysmex Corp.) is a new haemostasis analyser with blood coagulation, amidolytic, immuno‐turbidometric and light transmission aggregometry (LTA) capabilities. Transmitted light is monitored at multiple wavelengths (340, 405, 575, 660, 800 nm), from an LED light source.

Aims

To evaluate the performance of the CN‐6000 against a predicate device.

Methods

The CN‐6000 was evaluated against the CS‐5100 (Sysmex) for 14 different tests, using 880 samples from normal subjects, anticoagulated patients, critically ill patients, plasmas with high or low fibrinogen content or abnormal levels of interfering substances. Between‐day assay imprecision was assessed using commercial QC materials (n = 10 replicates on each of 5 days).

Results

Acceptable levels of imprecision were obtained for all assays. Agreement between the two analysers was excellent for all assays. Throughput was 35% higher using the CN‐6000 (337 vs 250 tests per hour for PT, aPTT and fibrinogen). The CN‐6000 also demonstrated improved clot detection in plasmas with high levels of interfering substances as demonstrated by a 29% reduction in “vote‐outs” due to low light transmission (24 vs 34).

Conclusions

The CN‐6000 demonstrated excellent comparability with the predicate instrument and acceptable levels of imprecision in all assays. Improvements in throughput and clot detection in the presence of interfering substances were also shown.

The Sysmex CS-5100 coagulation analyzer offers comparable analytical performance and excellent throughput capabilities

Objectives

This study compared the new high-volume blood coagulation analyzer Sysmex CS-5100 System™ (Siemens Healthcare Diagnostics, Erlangen, Germany) to the mid-volume blood coagulation analyzer Sysmex CS-2000i System™ (Siemens) for analytical performance. Additionally, the operational performance of the Sysmex CS-5100 System was compared with the blood coagulation analyzer ACL TOP 700 (Instrumentation Laboratory, Werfen Group, Kirchheim bei Munchen, Germany).

Materials and methods

We compared the Sysmex CS-5100 to the Sysmex CS-2000i and the ACL TOP analyzer for routine coagulation, chromogenic and immunological assays. Imprecision studies were performed for the Sysmex CS-5100 and Sysmex CS-2000i systems. A throughput and STAT analysis comparison of the CS-5100 and the ACL TOP was performed. A stress test was performed to characterize the robustness and the error rate of the CS-5100. We also performed correlation analysis between the CS-5100 and the CS-2000i or the ACL TOP in the measurement of patients’ samples.

Results

The inter-assay precision using the CS systems was impressive (inter-assay CV generally <3.5%) and the correlation between the two Sysmex analyzers was excellent. In the throughput study, the CS-5100 completed the measurement of 100 samples (210 results) in less than 49 min.

Conclusions

Our results demonstrated that the CS-5100 is a robust high-throughput analyzer, well-suited for coagulation laboratories.

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We show a comparison between the CS-5100, CS-2000i and ACL TOP 700.

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CS-5100 is a high-volume coagulation analyzer with excellent inter-assay precision.

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The system has a considerable high throughput and a good software usability.

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The software was simple, intuitive to use and offers various monitoring possibilities.