Immunoturbidimetric measurement of transferrin

This paper describes the development of an automated immunoturbidimetric assay for transferrin on a centrifugal analyser. Regression analysis of transferrin values measured immunoturbidimetrically demonstrates good agreement with data obtained by radial immunodiffusion (y = 0.997 + 0.024 g/l, r = 0.980, n = 50). The assay has a detection limit of 1.0 g/l and working range of approximately 1.0 to 6.0 g/l of transferrin. Day-to-day coefficient of variation is less than 3.5%. Immunoturbidimetric transferrin (g/l) and total iron binding capacity values (mumol/l) were compared using an established total iron binding capacity method (y = 0.050 X - 0.030 g/l, r = 0.967, n = 50). Minimal interference was found for lipaemic, haemolysed or icteric samples. Transferrin reference values with a mean of 3.05 g/l and 95% limits from 2.45 to 3.65 g/l were derived using serum from 300 apparently healthy subjects (150 males, 150 females). We conclude that the proposed transferrin method is more reliable and easier to perform than presently available total iron binding capacity methods.