engleski

Investigation of patient samples quality control usability in assessment of solid immunoassay performance consistency: experience from six months foffow-up

Use of manufacturer-independent quality control samples, especially clinical controls, has been encouraged for the long term assessment of autoimmune diagnostic test performance consistency. We aimed to compare the assessment of performance consistency for quantitative fluorescence enzyme immunoassays for detection of autoantibodies (EliA, Thermo Scientific) using manufacturer dependent (MQC) and clinical QC samples (CQC). In parallel we investigated the stability of CQC samples over time in conditions declared by the manufacturer. From January to June 2015 both positive and negative CQC were tested together with MQC in each run of measurement (EliA, Phadia 100, Thermo Scientific) of the following autoantibodies: anti-tissue transglutaminase IgA (anti-tTG IgA), anti-cyclic citrullinated IgG (anti-CCP), anti-cardiolipin IgG and IgM (aCL IgG, aCL IgM), anti-proteinase 3 IgG (anti-PR3) anti-myeloperoxidase IgG (anti- MPO) Our results showed acceptable precision for CQC as well as for MQC during the whole tested period for all respective antibodies. However, after four to five months, the positive CQC values tend downward for all except aCL IgM (tend upward). Use of CQC samples has advantages over MQC in terms of commutability, cut-off level precision assessment and potential ability for long-term follow-up, but also some disadvantages such as unknown stability or influence of endogenous substances.

autoantibodies ; quality control ; control samples

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