Acute phase reactants in the diagnosis of soft tissue infections of the upper extremity

Upper extremity soft tissue infections are commonly encountered in emergency department settings and often require timely interventions. Acute phase reactants, such as C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and white blood cell count (WBC), are commonly used in diagnostic workups. However, the utility of these biomarkers in the management of upper extremity infections remains uncertain. This study evaluates the diagnostic value of these acute phase reactants in a broad cohort of patients requiring intervention for upper extremity infections.

A retrospective review over five years identified 103 patients with upper extremity infections who required incision and drainage. The study found variable sensitivity and reliability of acute phase reactants, particularly for infections distal to the wrist. The average ESR was 42 mm/hr, CRP 64.1 mg/L, and WBC 10.5 × 10³/uL. Of patients with normal acute phase reactants, all had infections located at or distal to the wrist. Notably, patients with culture-negative infections did not exhibit significant differences in laboratory values compared to those with positive cultures.

Our study highlights the limitations of acute phase reactants as diagnostic tools for upper extremity infections, particularly in cases involving infections distal to the wrist. Despite the frequent elevation of these markers in infections requiring surgical intervention, they should not be relied upon as sole determinants of management. A thorough clinical examination and history remain critical in guiding treatment decisions. This study underscores the need for caution when using these biomarkers to rule in or rule out infection in the emergency department.