Diagnosis in contemporary medicine is made using an underlying classification system or nosology, the basis of which was first laid down at the end of the 18th century. The International Classification of Disease (ICD) was constructed to formalise this nosology, and successive revisions have attempted to capture technical developments and new discoveries across the diagnostic landscape. The ICD has proved particularly applicable in hospital practice where a selected patient population and access to comprehensive diagnostic aids enable a pathology-based diagnosis. When it came to be applied to primary care in the middle of the 20th century, however, it encountered major problems as general practice struggled to marry a classification of disease to the rawness of undifferentiated human illness and distress. Eventually, a classification based on the reason the patient consulted emerged to replace that based on pathology-defined disease. Analysis of the frontier zone where a dominant classification system struggles to maintain order reveals the ways in which medical nosologies, through their application in the process of diagnosis, attempt to promote and maintain a certain medical reality.                              

Marc Verbeke M.D., Diëgo Schrans M.D., Sven Deroose M.D., Jan De Maeseneer M.D. Ph.D
 Department of General Practice and Primary Health Care, Ghent University, Belgium
Abstract.
The International Classification of Primary Care (ICPC) has become a standard all over the world. It became a standard tool to classify the important elements in the Electronic Patient Record (EPR) of the GP: reasons for encounter (RFE) reflecting the patient’s view, process of care (decision, action, intervention or plans) reflecting the care process, and the assessment (diagnosis or health issue) reflecting the doctor’s view. ICPC-2 is fully compatible with structuring data in the episode of care model and it’s reflecting the essential elements of each patient/provider encounter. To implement ICPC-2 in the EPR a Thesaurus has been developed in Belgium with double encoded clinical labels. The implementation is now mandatory for labelled EPR systems in Belgium. The use of ICPC 2 may improve the accessibility and use of online Expert systems and Guidelines. Keywords: Medical Informatics, ICPC, primary care, thesaurus, medical record

Abstract Background and Objective:
 Family physicians (FP) play a key role in the diagnosis and treatment of health problems in the community and for evidence-based guidance, clinical research must be based on primary care data. This paper analyses the state-of-the-art approaches to the collection of data and the building of databases in family practice.
Methods:
 Experience in the Netherlands in family practice-based research networks (PBRNs) is explored in registering and analyzing primary care data, illustrated with four examples of PBRN studies.
Results:
 PBRNs bring together practices and FPs with a research interest to collect data and pursue research under routine patient care conditions. This directs research at relevant questions of family practice. Important features of success are practitioners’ ownership of data and the use of data in improving the care of patients in the participating practices. International standardization of terminology and definitions in the international classification of primary care improves the scientificquality of data recorded in registration networks and PBRNs.
Conclusions:
 Through primary care registration networks and PBRNs it is possible to tap in unselected care of patients and at the same time produce scientifically rigorous data. This enables research that represents the realities of primary care with valid data.