Q: How can I make the Area Under the Curve a fitted variable?

A: You can calculate the Area Under the Curve for any generic function of the parameters or of the compartmental masses that can be associated to a sample, such as in

where alpha is an adjustable parameter and q1 and q2 are the masses in compartment 1 and 2 respectively. The Area Under the Curve can then be calculated by checking "Calculate AUCs" in the Settings window and can be viewed using the "AUCs" option in the "Show" menu.

One could conceive of a situation where the AUC for a generic function is an optimized variable. This is not currently possible using the "Calculate AUCs" option in SAAM II. However, it can be done anyway by exploiting some existing SAAM II features.

Suppose the user wants to calculate the AUC of s1given above. The following steps show how:

1. Draw a compartment with a single input as in this figure:
   
   
2. Define the equation describing ex1 to be equal to s1. From standard differential equation theory, it is apparent that the calculated value of q1 will be the value of AUC of s1 at any time.
3. Associate q1 to your value of AUC at the given time. Be sure to use Absolute Weighting (remember that Relative weighting is not appropriate when a data set is made of a single data point) #
4. Fit the model. The kinetic data and the AUC will be taken to be variables to be fitted at the same time

<< Back to Support Page