[Thea value and limits to kinetic analysis of human serum Ig. Preliminary note]

We have considered accuracy and sensitivity of a new kinetic method called "Fixed time", in order to determine human Ig. The method based on velocity of the reaction, considers the increase in turbidness, which is due to immune-complex formation during a constant and predetermined period of time from the start of the reaction to when equilibrium is achieved. Experience with testing times demonstrates that the best results were obtained by introducing a variant to the method adopted up to now. According to that method, velocity reaction was usually estimated in a period of time comprised between the 1st and the 6th minute, while turbidness is now estimated after 15" (first time) and after 3'15" (final time) from the beginning of the reaction.