Standard TNF alpha was titrated on Anti-TNF alpha Affibody® molecule coated plates with a sensitivity of 60 pg/ml. QUANTITATIVE ELISA The Anti-TNF alpha Affibody® molecule can be used as capture reagent in a sandwich ELISA in combination with a mouse anti-human TNF-alpha monoclonal antibody as the detection reagent. Titration of TNF-alpha gives a sigmoid curve with a sensitivity of 60 pg TNFalpha/ ml (defined as two times background value) and a measurement interval between 100 and 1000 pg/ml.