Nephelometric assay of staphylococal coagulase.

Stutzenberger, Fred J. (Michigan State University, East Lansing), Charles L. San Clemente, and Dharam V. Vadehra. Nephelometric assay of staphylococcal coagulase. J. Bacteriol. 92:1005-1009. 1966.-Clotting of fibrinogen by staphylococcal coagulase was accompanied by an increase in light scattering; this property was used as a basis for a new nephelometric method. Reaction rates, which were now easily and precisely measured, were found to be directly proportional to coagulase concentration, when optimal conditions were maintained. These conditions included pH and concentrations of fibrinogen, coagulase-reacting factor, and sodium chloride in the reaction mixture. A standardized procedure for the assay is outlined, and a unit for the expression of activity is proposed.