Rapid and precise whole blood protamine titration.

A rapid and precise whole blood protamine titration method was developed. The method uses azure A dye as the titration indicator and thereby replaces the tedious and time-consuming clotting assay with a facile colorimetric assay. The method provides the same accuracy in estimating the titration end-point, but allows the processing time to be shortened to that required by current clinical methods. The simplicity, flexibility, speed, and accuracy offered by the method, and the ability to use whole blood specimens for the measurements, should allow the method to be used by clinicians in the operating room or during a surgical procedure to estimate the adequate protamine dose required for heparin reversal.