Confidentiality of patient data in the field of medical informatics is an important task. Leaked sensitive information within this data can be adverse to and being abused against a patient. Therefore, when working with medical data, appropriate and secure models which serve as guidelines for different applications are needed. Consequently, this work presents a model for performing a privacy preserving record linkage between study and registry data. The model takes into account seven requirements related to data privacy. Furthermore, this model is exemplified with a study on family based colorectal cancer in Germany. The model is very strict and excludes possible violations towards data privacy protection to a reasonable degree. It should be applicable to similar use cases which are in need of a mapping between medical data of a study and a registry database.