The sequential steps for converting blood measurements to an input curve are explained in a dedicated section. The current plasma fraction model serves for converting a whole-blood activity curve into a plasma-activity curve.
It is assumed that a whole-blood activity curve has been loaded with Load Whole Blood Activity entry in the menu.
With the Fix model the activity concentration in plasma is assumed to be proportional to the activity concentration in whole blood. The proportionality constant Fraction has to be specified by the user and has a default of 1.
Note that as long as no other plasma-related data is loaded or the plasma fraction changed, the Fix model is applied so that the whole-blood activity curve will be used as the input curve.
There is nothing to fit with the Fix model.