Calprotectin levels in oral fluids: the importance of collection site

Calprotectin is a major protein of granulocytes and monocytes with antimicrobial properties, and is released during activation or cell death. In the present study the levels of calprotectin in various oral fluids were analyzed in 12 healthy adults using different collection devices. Parotid saliva, stimulated whole saliva and "mucosal transudate" were collected and analyzed by enzyme-linked immunosorbent assay (ELISA). The results showed mean concentrations of 3.2, 22.0 and 40.9 mg/l in the respective oral fluids, illustrating great variation of calprotectin levels between different oral fluids. The results are in accordance with the composition of these saliva samples; the lowest calprotectin level was obtained in parotid saliva, which contains the purest secretion. These findings illustrate the importance of careful sampling procedures. The levels of salivary calprotectin are markedly influenced by the site of collection.