In connection with investigations related to mathability and to applications of computer-assisted methods for studying a validation of Electromagnetic Compatibility (EMC) tests is presented. This paper presents a validation of Electromagnetic Compatibility (EMC) tests performed in Gigahertz Transverse Electromagnetic (GTEM) cells as an alternative method to tests performed at Open Area Test Sites (OATS) or expensive anechoic chambers. The equipment selected for the inspection is widely used in electronic devices of crucial reliability expectations like medical measurements or electronic components for transport and industrial process control. This special engineering topic gives a good example of the wide applicability of mathability.