Abbott D-dimer assay: analytical performance and diagnostic accuracy in management of venous thromboembolism

This study aimed to assess analytical characteristics and diagnostic accuracy in management of venous thromboembolism (VTE) in the Emergency Department (ED) of the Abbott D-dimer assay applied on the Alinity c clinical chemistry analyzer (Abbott Laboratories, Chicago, IL) compared to the INNOVANCE D-dimer assay (Siemens Healthineers, Marburg, Germany). Precision was determined at three concentration levels following the CLSI EP15-A3 protocol. Method comparison and diagnostic accuracy were assessed using samples obtained from 85 patients who were referred for diagnostic imaging and D-dimer testing due to clinically suspected VTE. Within-run coefficients of variation (CVs) were 3.0%, 0.5% and 0.5% at D-dimer concentrations of 0.54, 1.42 and 2.68 mg/L FEU, while respective between-run CVs were 2.0%, 3.4% and 2.7%, hence fulfilling the desirable biological variation criteria for imprecision (<12.6%). Passing-Bablok regression analysis yielded a small proportional difference between the two compared assays (y = 1.09 (95% confidence interval (CI): 1.01-1.18) x + 0.09 (95%CI: -0.09 to 0.16)), while Bland-Altman analysis showed significant negative absolute (-0.6 mg/L FEU, 95%CI: -0.9 to -0.3) and relative mean bias (-14.1%, 95%CI: -20.3 to -7.9). Spearman's ρ was 0.979 (95%CI: 0.967-0.986). Inter-assay agreement relative to the cut-off was 92% (kappa coefficient = 0.547 (95%CI: 0.255-0.839)). Diagnostic sensitivity, specificity, positive and negative predictive values of the Abbott assay were 100%, 9.2%, 25.3% and 100%, respectively, compared to the following data for the INNOVANCE assay: 95.0%, 15.4%, 25.7% and 90.9%. Abbott D-dimer assay has shown excellent analytical precision, high comparability with the INNOVANCE D-dimer and high NPV at manufacturer's cut-off.

Diagnostic validation and development of an algorithm for identification of intussusception in children using electronic health records of Ningbo city in China

BACKGROUND

Monitoring the risk of intussusception after the introduction of rotavirus vaccines is recommended by the World Health Organization (WHO). Although the validity of intussusception monitoring using electronic health records (EHRs) has been confirmed previously, no similar studies have been conducted in China. We aimed to verify the diagnosis and determine an algorithm with the best performance for identification of intussusception using Chinese EHR databases.

RESEARCH DESIGN AND METHODS

Using the Regional Health Information Platform in Ningbo, patients aged 0-72 months from 2015 to 2021 with any related visits for intussusception were included. The algorithms were based on diagnostic codes or keywords in different clinical scenarios, and their performance was evaluated with positive predictive value (PPV) and sensitivity in line with the Brighton guidelines.

RESULTS

Brighton level 1 intussusception was confirmed in 2958 patients with 3246 episodes. Fine-tuned algorithms combining the appearance of the relevant ICD-10 codes or the Chinese keyword 'Chang Tao' in any diagnostic reports with the results of enema treatments or related surgeries showed the highest sensitivity, while the highest PPV was obtained by further criteria based on typical radiographic appearances.

CONCLUSION

Intussusception could be identified and validated internally using EHRs in Ningbo.

Orthopox viruses and the safety margins of solvent-detergent treated plasma-derived medicinal products

BACKGROUND

The currently ongoing outbreak of monkeypox virus in many non-endemic countries around the world has also raised concerns about the safety of plasma-derived medicinal products. Based on what is known about the poxviridae, that is, that members are exceedingly large and carry a lipid envelope, effective removal and inactivation by plasma product manufacturing processes is expected. For the widely used solvent-detergent (S/D) treatments, however, poxviruses have been reported as potentially being a bit more resistant.

STUDY DESIGN AND METHODS

Using a S/D mixture comprising tri-n-butyl-phosphate, polysorbate 80 and Triton X-100 (TX-100), inactivation of vaccinia virus (a model closely resembling monkeypox virus, both within the same genus, i.e., Orthopoxvirus) in a plasma-derived process intermediate was analyzed over 60 min. As use of Triton X-100 will, based on environmental concerns, be restricted, similar experiments were conducted with a physicochemically virtually identical alternative, Nereid.

RESULTS

Fast inactivation of vaccinia virus to the assay detection limit, that is, reduction of infectivity by greater than 4 log₁₀ within 10-20 min, was measured for the TX-100 S/D mixture. The alternative S/D mixture (Nereid instead of TX-100) was found fully equivalent.

CONCLUSION

As for other lipid-enveloped viruses, treatment of process intermediates with S/D mixtures containing TX-100 or the closely related detergent Nereid are highly effective in inactivating poxviruses. Thus, the current spread of monkeypox virus does not compromise the viral safety margins of plasma-derived medicines.