Cutting edge confusion about cut-off settings in autoimmune diagnostics.

In autoimmune diagnostics results are interpreted in relation to a single or multiple cut-off value(s) in order to decide if the test is negative, weak positive, positive, or even strong positive. The way a cut-off is established appears to be very heterogeneous and this hampers harmonization of test results obtained in assays, either established in-house or obtained from different companies. In this context it is surprising that in diagnostic and classification criteria for distinct autoimmune diseases referral is made to cut-off values with the intention of harmonization.

A Comparative Study of Nine SARS-CoV-2 IgG Lateral Flow Assays Using Both Post-Infection and Post-Vaccination Samples.

Background: Since the SARS-CoV-2 pandemic, lateral flow assays (LFA) detecting specific antibodies have entered the market in abundance. Despite being CE-IVD-labeled, the antigenic compounds of the assays are often unknown, the performance characteristics provided by the manufacturer are often incomplete, and the samples used to obtain the data are not detailed.

Objective: To perform a comparative evaluation of nine lateral flow assays to detect IgG responses against SARS-CoV-2.

Validation conform ISO-15189 of assays in the field of autoimmunity: Joint efforts in The Netherlands.

ISO 15189:2012 requires validation of methods used in the medical laboratory, and lists a series of performance parameters for consideration to include. Although these performance parameters are feasible for clinical chemistry analytes, application in the validation of autoimmunity tests is a challenge. Lack of gold standards or reference methods in combination with the scarcity of well-defined diagnostic samples of patients with rare diseases make validation of new assays difficult.

Serum soluble interleukin-2 receptor measurement in patients with sarcoidosis: a clinical evaluation.

Objectives: To date, insufficient evidence is available to recommend serum soluble interleukin-2 receptor (sIL-2R) measurement as a routine test in the assessment of sarcoidosis. Therefore, we evaluated the clinical value of this test.

Design: Forty-seven patients with sarcoidosis, all presenting with active disease, were included in the study.