The identification of reliable quality indicators (QIs) in the total testing process (TTP) represents a crucial step in enabling users to quantify the quality of laboratory services, but the current lack of attention to extra-laboratory factors is in stark contrast with the body of evidence showing the multitude of errors that continue to occur in the pre- and post-analytical phases. Although interesting programs on indicators of the extra-analytical phases have been developed in some countries, there is no consensus on the production of joint recommendations for the adoption of universal QIs and the use of common terminology in the total testing process. In view of the different QIs and terminologies currently used, there an urgent need to harmonize proposed QIs, which should comply with three main principles: they must be patient-centered, consistent with the requirements of the International Standard for medical laboratories accreditation, and address all stages of the TTP. A model of quality indicators (MQI), consensually developed by a group of clinical laboratories according to a project launched by a working group of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC), includes 56 QIs related to key processes (34 pre-, 7 intra- and 15 post-analytical phase) and three to support processes. The scope of harmonization in laboratory medicine, more far-reaching than method harmonization, should cover a wider range of topics, namely all steps of the “brain-to-brain loop”. The identification of valuable QIs is a key step in paving the way towards quality and patient safety in laboratory medicine.