2026 Volume 75 Issue 2 Pages 335-343
Serum soluble interleukin-2 receptor (sIL-2R) measurement is a useful diagnostic aid and a monitoring tool for malignant lymphoma. The latex turbidimetric immunoassay-based reagent ‘Nanopia IL-2R’ (Sekisui Medical Co., Ltd.) can be used for measurements with general-purpose automatic analyzers, including LABOSPECT008. However, previous reports indicated that Nanopia IL-2R showed false high or low values in some samples caused by a nonspecific reaction with immunoglobulins. We evaluated the basic performance of the improved N-type Nanopia IL-2R reagent [(N) Nanopia IL-2R], and examined its correlation with the enzyme immunoassay, IL-2R Test [IL-2R・BML: BML Inc.], and the influence of renal function on this correlation. The performance of (N) Nanopia IL-2R for precision and dilution linearity was satisfactory. Although the correlation coefficient with IL-2R・BML was good (r = 0.956), the regression equation showed a positive slope (y = 1.063x + 106.4). There were three discrepant cases, and one nonspecific reaction was documented by dilution analysis. However, dithiothreitol treatment of the discrepant samples indicated no involvement of IgM. Furthermore, while no obvious effect of renal function on correlation was observed, increased sIL-2R levels, as measured by (N) Nanopia IL-2R, may differ depending on renal function. The (N) Nanopia IL-2R reagent demonstrated excellent basic performance and no obvious non-specific reactions caused by IgM. Since the reagent is compatible with general-purpose analyzers, it is suitable for pre-consultation testing and is expected to contribute to clinical practice.
