Economic Evaluation of Combined Testing Strategies Using Erythrocyte Sedimentation Rate and C-Reactive Protein Tests

Objective: To conduct an economic analysis of the use of combined ESR (Erythrocyte Sedimentation Rate) and CRP (C-Reactive Protein) testing strategies compared to CRP testing alone in U.S hospitals. Methods: A decision tree model was developed to evaluate the cost-effectiveness and cost-benefit of combined ESR and CRP testing compared to CRP alone. The model estimated the laboratory costs, number of misdiagnoses, and follow-up costs associated with misdiagnoses. Model inputs were sourced from published literature and clinical guidelines. Two combined testing strategies were evaluated: 1) result is positive only if both ESR and CRP results are positive (ESR + CRP) and 2) result is positive if either the ESR or CRP result is positive (ESR/CRP). Strategies were evaluated for five individual and three grouped conditions. Results: Results demonstrated that the ESR + CRP testing strategy is a cost-effective strategy for reducing misdiagnoses and is expected to result in a net cost reduction to the healthcare system when accounting for the reduction in follow-up costs associated with misdiagnoses. In contrast, the ESR/CRP strategy led to increased misdiagnoses when compared to CRP alone. Conclusion: Results indicate that adopting the ESR + CRP strategy would reduce misdiagnoses and overall costs to healthcare systems.