The accuracy can be calculated from the "Confusion matrix".."plotconfusion()" is the matlab syntax ...from the confusion matrix we can calculate the accuracy, sensitivity,specificity, accuracy , PPV, NPV etc..pls follow the reference
Step 1 : After training phase,feed the test feature set in your system (you can use fuzzy toolbox in matlab for this purpose)
step 2 : compute the confusion matrix using matlab syntax " plotconfusion"..you will get the confusion matrix values of desired vs predicted diagnosis.
step 3 :The confusion matrix contains the values of TP, TN, FP, FN.
Step 4: Calculate the accuracy,specificity using the above TP, TN, FP, FN values.
( for these calculations, you can use the tutorial attached in my previous response ).