Abstract: The invention relates to a water-based preparation to be mixed with blood, containing citrate ions which inhibit coagulation, as well as a method applied at collection of blood from a living organism while adding an anticoagulant substance including citrate ions. The new features of the invention are that acetate, being a physiologic energy source, inter alia for platelets, is included in the preparation and is added to the blood during collection in addition to the anticoagulant substance in order to obtain prolonged shelf-life of the platelet concentrate without increased risk for the donor or patient.

Abstract: A method for the detection of antibodies immunochemically bound to the corresponding antigen fixed to a smooth surface of glass, metal, polymerfilm or the like. The surface with antigen bound antibodies is contacted with a suspension of small water-insoluble particles to which a biopolymer is directly bound, said biopolymer having the ability of binding to said antibodies, preferably at a non-antigen binding structure of the antibodies. The particles are then adsorbed only on that part of the surface where antibodies are specifically bound and the adsorbed particles forms a coating that is clearly visible by the eye.