Xiehe Yixue Zazhi (Sep 2023)
Clinical Evaluation of a Fluorescence Immunochromatographic Assay for Interleukin-6 Detection
Abstract
Objective To evaluate the performance of a new fluorescence immunochromatographic assay for interleukin-6 (IL-6) detection. Methods A total of 104 serum samples from patients with suspected infections and normal population were collected at Peking Union Medical College Hospital in December, 2021. Assay A (Wanfu biofluorescence immunochromatography assay) and B (Siemens chemiluminescence assay) were used as references to evaluate the equivalence of the Innova assay for detecting serum IL-6. Meanwhile, 39 homologous paired plasma and serum were collected to evaluate the consistency of the Innova assay in detecting IL-6 content in different types of samples. Results In quantitative analysis, two samples were excluded because the content was above the limit of detection for method B. Compared with the assay A or B, the regression equations of the Innova assay were Y=-7.0950+1.1924X (R2=0.9448), Y=-2.6143+1.3072X (R2=0.9391), and the Pearson correlation coefficients were 0.9720 and 0.9691, respectively. With assay A or B as reference, the Innova assay showed the Bland-Altman bias values of -3.0 and 8.0, while the expected bias at the medical decision level (7 ng/L) was -1.44 ng/L (95% CI: -5.37 to 2.50), 1.97 ng/L (95% CI: -2.09 to 6.01), respectively, with 95% CI intervals all included permissible errors (±15%, -1.05 to 1.05 ng/L). The qualitative results showed the high total coincidence rate between the Innova assay and assay A (84.6%), and assay B (83.7%). In addition, the consistency of the Innova assay was good for 39 homologous pairs of plasma and serum samples (P < 0.0001). Only one data (2.6%, 1/39) was identified by Bland-Altman bias analysis to be outside the maximum allowable error range. Conclusions Compared with the two reference assays with the same or different principles used in clinical practice, the Innova assay for IL-6 detection has good consistency and correlation, and its test results are almost not affected by the type of serum/plasma samples. To a certain extent, the Innova assay meets the needs of rapid detection in clinical practice.
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