The efficacy of cell collection devices with a cytologic brush depends on the diameter of the bristles, not on the diameter of the brush

It is thought that bronchoscopic brushing and the associated devices have already been established. We, however, found that the various types of brushes used throughout the world vary greatly in their ability to collect cells. With several brushes, the numbers of obtained cells were found to be small, and most cells showed air-dried artifacts. We examined factors influencing cell collection with cytologic brushes. Four cytologic brushes and three prototype brushes were examined. The bronchi of eight pig lungs were brushed, then the numbers of collected cells and cells with air-dried artifacts were counted. The diameter of the whole brush and its length did not affect the total number of collected cells. A total of 56 specimens were obtained. Numbers of collected cells with brushes having bristles less than 0.1 mm in diameter were significantly greater than the numbers collected with brushes having bristles 0.1 mm or more in diameter (P = 0.00003). The smaller the bristle diameter, the fewer the cells that showed air-dried artifacts. Bristle diameter of the cytologic brush is a key factor in cell collection efficacy. It is now recommended that attention should be given to the characteristics of cytologic brushes, and in particular to the diameter of the bristles.