If I get a call for transplant, will I definitely get the organ?

No, getting a call for transplant does not mean that you will definitely receive an organ. The transplant team will examine your immediate fitness for transplant. There is a possibility that the tests are done just before possible transplant may not be normal to make you fit for transplant. Further, more than one patient is called for possible transplant and it may be a chance that someone else will be more fit than you for that particular organ transplant.