[A method of determining the concentration of biologically active fibronectin].

The suggested method is based on the ability of fibronectin intact molecules to agglutinate gelatin-coated particles. Gelatin-coated particles have been prepared with the use of specially treated Staphylococcus epidermidis cells. The concentration of biologically active fibronectin has been measured using laser nephelometry and agglutination test in microtitre plates. The accuracy of the test is 4 mg/ml (laser nephelometer) and 0.1 mg/ml (agglutination test).