The total protein is measured using the Biuret procedure with bovine albumin as the standard; F/P ratio is calculated using absorbance at 491.5 nm. Care is taken to ensure complete removal of any free fluorescein from the final product. Antibody titer of the IgG is standardized with an in-house control by immunoelectrophoresis. The antibody reacts with native fibrinogen as well as with the fibrinogen fragments D, E, X and Y. Traces of contaminating antibodies have been removed by solid-phase absorption with human plasma proteins.