Development of a light-scattering immunoassay for thyroxine-binding prealbumin in plasma or serum

This paper describes the development of an assay for the measurement of thyroxine binding prealbumin in plasma or serum, based on the technique of fixed-time kinetic immunoturbidimetry with the Cobas Bio centrifugal analyser. The assay has good precision (coefficient of variation < 5%) and a detection limit of 15 mg l . The assay is rapid, economical, and the results compare well with those obtained by an established procedure. The technique has wide applicability to instruments which can make kinetic measurements and could prove useful in the clinical monitoring of patients receiving nutritional support and in the identification of nutritionally-at-risk groups prior to surgery. The assay further emphasises the sensitivity and usefulness of kinetic immunoturbidimetry for the measurement of low concentrations of proteins.