Randomization
bleeding
BLEEDING
Each nodule was sampled for four passes (twice with a stylet (S+) and twice without a stylet (S-)). The nodules were randomly divided (1:1) into S+ (order of the four passes; S+→S-→S+→S-) and S- (order of the passes; S-→S+→S-→S+) to avoid the effect of bleeding from the previous pass on the later pass specimen. The order of S+ or S- first pass was determined by a preprinted random sequence that was kept in an opaque sealed envelope that the operator opened after the patients confirmed their enrollment.