A gamma-ray analysis system is described for analyzing gamma-ray emitting radionuclides. The gamma-ray analysis system includes an analytical apparatus having a gamma-ray detector in operative communication with a modular and scalable shield assembly that encases a sample container having a sample to be tested. The detector communicates data to an electronic interface device that converts the data from an analog format to a digital format before a controller transmits the data to a central laboratory for further data processing, analysis and conclusion by qualified laboratory analysts. The controller runs an application software package on a graphic user interface that allows simple steps for conducting testing and data acquisition by the end user, while permitting real time data transmission between the field site and the central location. Functions were implemented for ensuring laboratory quality results while removing knowledge and experience requirements of an end user.