OBJECTIVES: To study the inter-practice variability in Spain--by institution, management, and regional characteristics--of the frequency and appropriateness of test requests made by primary care practitioners for acute phase markers. STUDY DESIGN: Observational cross-sectional study. METHODS: One hundred forty-one clinical laboratories were invited to participate by providing the number of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and complete blood count (CBC) tests requested by general practitioners. We calculated the ratio of test requests per 1000 inhabitants, ratios of related test requests, and variability index (90th percentile/10th percentile). We compared the results among the different areas according to their setting, location, and management. RESULTS: We recruited 64 laboratories (14,846,065 inhabitants). There were almost twice as many ESR requests as CRP requests; the variability index for ESR was almost double that of CRP. Furthermore, the latter was underrequested in rural-urban areas compared with rural. The ESR/CBC and ESR/CRP ratios are lower in institutions with private management, and the number of ESR requested in institutions with private management are lower than that of public. The differences among Spanish regions were reported for ESR per 1000 inhabitants, ESR/CBC, and ESR/CRP. CONCLUSIONS: There was significant variability in the requests made by primary care practitioners for patients' acute phase markers. Rates were influenced by geographic location, hospital setting, and institution management. ESR was inappropriately overrequested; strong efforts should be made to adjust the requests of ESR and to standardize the use of CRP measurement.
OBJECTIVES: To study the inter-practice variability in Spain--by institution, management, and regional characteristics--of the frequency and appropriateness of test requests made by primary care practitioners for acute phase markers. STUDY DESIGN: Observational cross-sectional study. METHODS: One hundred forty-one clinical laboratories were invited to participate by providing the number of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and complete blood count (CBC) tests requested by general practitioners. We calculated the ratio of test requests per 1000 inhabitants, ratios of related test requests, and variability index (90th percentile/10th percentile). We compared the results among the different areas according to their setting, location, and management. RESULTS: We recruited 64 laboratories (14,846,065 inhabitants). There were almost twice as many ESR requests as CRP requests; the variability index for ESR was almost double that of CRP. Furthermore, the latter was underrequested in rural-urban areas compared with rural. The ESR/CBC and ESR/CRP ratios are lower in institutions with private management, and the number of ESR requested in institutions with private management are lower than that of public. The differences among Spanish regions were reported for ESR per 1000 inhabitants, ESR/CBC, and ESR/CRP. CONCLUSIONS: There was significant variability in the requests made by primary care practitioners for patients' acute phase markers. Rates were influenced by geographic location, hospital setting, and institution management. ESR was inappropriately overrequested; strong efforts should be made to adjust the requests of ESR and to standardize the use of CRP measurement.