Non-specific Activities against Ruthenium Crosslinker as a New Cause of Assay Interference in an Electrochemilluminescent Immunoassay

Abstract

Abstract

Two cases of antiruthenium antibody interference in Modular free thyroxine assay

“…Allthough ruthenium was also present in the TSH assay, we did not observe its interference in that assay. Although our results are in accord with the previous studies, 5,6 we do not have an explanation of why the interference is not seen in the TSH assay.…”

“…Interference of antiruthenium antibodies in the Roche fT3 assay has been described previously. 5,6 Sapin et al described that the antiruthenium antibodies in their study did not interfere with the fT4 assay, and in the paper of Ando et al antiruthenium antibodies seemed to interfere at least partially in the fT4 assay, but could not be confirmed. In our patients, the interference of the antiruthenium antibodies was similar in the fT4 and the fT3 assay.…”

Falsely elevated thyroid hormone levels caused by anti-ruthenium interference in the Elecsys assay resembling the syndrome of inappropriate secretion of thyrotropin

“…for FT3 and FT4 [7]. Subsequently, similar interference, for competitive total T4 and sandwich TSH was confirmed by Mandel et al [9] and Buijis et al [10].…”

“…Elecsys, referred to as Eclusys in Japan, is an electrochemiluminescent immunoassay (ECLIA) involving ruthenium as the luminescent material [6]. Although this fully automated rapid assay provides prompt diagnosis of patients with thyroid disease, and has about 25% of the market share in Japan (Roche Diagnostics, personal communication, November 27, 2011), method-specific interference associated with ruthenium or streptavidin has been described previously [7][8][9][10]. After Roche Diagnostics introduced improved reagents for Elecsys, in the summer of 2006, Ando and colleagues first reported antiruthenium interference in competitive Elecsys assays the interfering factor could not be identified, anti-ruthenium interference may have accounted for the erroneous results in their patient.…”

“…For the competitive assay, the amount of emission produced by the excited ruthenium is inversely proportional to the concentration of the hormones present. By contrast, in the sandwich assay, the amount of emission correlates positively with the hormone levels [7,11]. Therefore, an interfering substance reduces the amount of emission produced by the excited ruthenium, resulting in falsely elevated or depressed hormone levels in the competitive or sandwich Elecsys assays [10]; a detailed description of the mechanisms involved has not been reported.…”