<p>A method for measuring a generation of thrombin in a sample of whole blood as a function of time includes adding to a sample of whole blood a fluorogenic substrate and a thrombin activator to form an activated sample. A conversion product is permitted to form in the activated sample. Fluorescence is measured as a function of time from a fluorescent group that is released during the formation of the conversion product with the use of a fluorescence detector. The fluorescence detector operates in an extended range mode and has an increased sensitivity. Thrombin generation as a function of time can then be calculated from the measured fluorescence as a function of time.</p>