Comparison of SIMOA and VEUS technologies for serum neurofilament light chain measurement in multiple sclerosis.

INTRODUCTION: The gold standard for serum neurofilament light chain (sNfL) determination is the single molecule array (SIMOA), the use of which is limited by availability and cost. The VEUS method is a fully automated, user-friendly diagnostic system requiring no sample preparation, with high reported sensitivity, multiplexing capability, and rapid diagnostics. The aim of this study was to compare the SIMOA and VEUS methods for determining sNfL levels in patients with multiple sclerosis (MS). METHODOLOGY: A single-centre cross-sectional study was conducted at the MS Centre of University Hospital Ostrava. Patients were enrolled in the study from January 18 to January 31, 2024. Inclusion criteria were: 1) diagnosis of MS according to the revised 2017 McDonald criteria, 2) age ≥18 years, and 3) signed informed consent. The NF-light V2 diagnostic kit (SIMOA, Quanterix) and the Singleplex Neurology assay kit (VEUDx, EZDiatech) were used to determine sNfL concentrations. The two methods were compared by use of Spearman correlation, Passing-Bablok regression, and Bland-Altman analysis. RESULTS: A total of 49 patients were included in the study, of whom 39 (79.6 %) were female. The median sNfL concentration was 7.73 (IQR 5.80-9.93) ng/L determined by SIMOA and 1.31 (IQR 1.18-1.65) ng/L by VEUS. We did not find a correlation between SIMOA and VEUS (rs = 0.025, p = 0.866). Passing-Bablok regression demonstrated a systematic and proportional difference between the two methods. A significant disagreement between them was also confirmed by the Bland-Altman plots. On average, sNfL values measured by SIMOA were 3.56 ng/L (95 % CI 0.78 to 6.34) higher than those measured by VEUS. CONCLUSION: Our investigation uncovered noteworthy disparities between the SIMOA and VEUS techniques in determining sNfL levels. Specifically, the VEUS technique systematically produces lower estimates of sNFL levels. This substantial variance emphasizes the importance of carefully evaluating assay methods when quantifying sNfL.

A comparison of measles-rubella-zoster reaction, oligoclonal IgG bands, oligoclonal kappa free light chains and kappa index in multiple sclerosis.

BACKGROUND AND OBJECTIVES: To evaluate the diagnostic performance of the measles-rubella-zoster reaction (MRZR) in a large real-world multiple sclerosis (MS) cohort. Second, to compare MRZR with the determination of oligoclonal IgG bands (OCB), oligoclonal kappa free light chain bands (oKFLC), and the KFLC index. METHODS: A single-center retrospective study was conducted at the University Hospital Ostrava (Czech Republic). Patients were eligible if aged ≥18 years with a determined clinical diagnosis. IgG antibodies against measles (M), rubella (R), and varicella zoster (Z) viruses were determined in paired CSF and serum using ELISA and MRZR indicated as positive if at least two components had an antibody index >1.4. OCB and oKFLC were detected by means of isoelectric focusing, and KFLC CSF and serum concentrations for calculation of the KFLC index were determined immunochemically. RESULTS: A total of 1,751 patients were included in the analyzed data set, which comprised 379 MS patients and 1,372 non-MS controls. The frequency of positive MRZR was higher in MS than in non-MS cases (MS 32.2 % vs non-MS 2.8 %; p < 0.001). This corresponded to a specificity of 97.2 % (95 % CI 96.1-98.0) and sensitivity of 32.2 % (95 % CI 27.5-37.2) and overall accuracy of 83.1 % (95 % CI 81.3-84.8). In comparison, the highest sensitivity of 95.6% (95 % CI 93.0-97.5) was for OCB with specificity of 86.9 % (95 % CI 84.9-88.7), followed by oKFLC with sensitivity and specificity of 94.7 % (95 % CI 91.5-96.9) and 78.4% (95 % CI 75.7-80.8), respectively, and the KFLC index with sensitivity of 92.5 % (95 % CI 86.6-96.3) and specificity of 93.5 % (95 % CI 90.5-95.9). DISCUSSION: MRZR remains a very specific test for the diagnosis of MS but has low sensitivity, which disallows its independent use. In contrast, OCB showed the highest sensitivity and thus remains the gold standard for the diagnosis of MS.

The importance of CT perfusion for diagnosis and treatment of ischemic stroke in anterior circulation.

Computed tomography perfusion (CTP) is a functional examination of brain tissue that characterises the state of cerebral perfusion and provides information about the current status of the circulation. CTP can improve diagnostic accuracy of ischemic stroke. Published studies showed that perfusion imaging improves the prognosis of patients with acute ischemic stroke in anterior circulation and allows patients to be referred for treatment outside the time window for administration of intravenous thrombolysis (IVT) or mechanical thrombectomy (MT). In this review we discuss technical aspects of CTP, clinical significance of CTP in anterior circulation stroke (ACS) and its role in diagnostics of stroke mimics.