C-REACTIVE PROTEIN IN GENERAL-PRACTICE - HOW COMMONLY IS IT USED AND WHY

Objective - C-reactive protein (CRP) is a well-known diagnostic tool i n general practice. The scope of this study was to assess how frequent ly CRP is used by general practitioners and to evaluate the reasons fo r using it. Design - A retrospective part based on data from a laborat ory database system, and a prospective part with a questionnaire-based registration. Setting - 30 general practice clinics in the catchment area of Vejle County Central Hospital. Subjects - Retrospectively, all patients from general practice serviced by the laboratory for one yea r. Prospectively, 1190 patients from whom a blood sample was taken for CRP-measurement during a 2 month study period. Main outcome measures - The frequency of using CRP and the reason requesting it; A) diagnosi ng a new disease, B) monitoring a well known disease, or C) ''screenin g''. Furthermore; 1) infections, 2) chronic inflammatory disease, 3) m alignant disease, or 4) others. Results - CRP-measurements were ordere d in 3.7% of all consultations in general practice and for 34.1% of al l patients whose blood sample was analysed at the central laboratory. The use of CRP was as follows: A-1: 28.6%, A-2: 6.7%, A-3,4: 9.3%, B-l : 8.2%, B-2: 12.4%, B-3,4: 6.5%, C-l: 5.7%, C-2: 3.2%, C-3: 3.5% and C -4: 15.2%. Diagnosing a new (infectious) disease was the most frequent single reason for CRP-measurement. There was major interpractice vari ation. Conclusions - CRP is frequently used in general practice, mostl y (65.4%) in the field of infections and chronic inflammatory diseases . Because of major interpractice variation, the most correct way of us ing CRP should be evaluated and guidelines should be provided.