Evaluation of the QUANTUM BLUE sCAL rapid test as a point of care tool to identify patients with peritonsillar abscess

Abstract

S100A8/A9 (Calprotectin) serves as a biomarker for various inflammatory diseases, such as for peritonsillar abscess (PTA). Recently, the PTA score was developed for reliable PTA identification. It uses a combination of characteristic clinical symptoms and elevated calprotectin levels in serum and saliva to determine this score. Although well-established point-of-care tests (POCT) to determine serum or faecal calprotectin levels exist, a reliable and rapid tool to analyse salivary calprotectin has not yet been described. In this study, we analysed the potential of the QUANTUM BLUE sCAL Test (QBT, BÜHLMANN Laboratories AG, Switzerland) to determine S100A8/A9 levels during outpatient management. These QBT measurements are combined with other clinical factors to determine the PTA score. Significantly higher calprotectin levels were determined by QBT in patients with PTA compared to healthy controls. The receiver operating characteristic (ROC) curves for the QBT revealed cut-off values of 2940 ng/ml (sensitivity = 0.88, specificity = 0.78) in serum and 5310 ng/ml (sensitivity = 0.80, specificity = 0.50) in saliva. By adding the QBT results to determine PTA values, a ROC analysis provided a statistical cut-off score of 2.5 points to identify the existence of a PTA with a sensitivity of 100% and a specificity of 89.3%. The QUANTUM BLUE sCAL Test (QBT) is an appropriate POCT to determine serum and salivary calprotectin levels. Thus, PTA scores can be determined within a short time frame by applying the QBT during outpatient management.