Sir,I read with great interest the recent publication on atypical category in voided urine samples.[1] Mokhtar et al. concluded that “The atypical category diagnosis is associated with a significant proportion of urothelial carcinoma.”[1] I have some comments on this work. Due to the nature of the retrospective study, the value of this report is limited. At first, we are not aware whether all urine samples were collected in a correct manner. The pre-analytical error in sample collection seems to be an important factor in laboratory medicine.[2] Second, the cytology requires the experience of a microscopist. Hence, the effect of difference in experience of the practitioners is questionable.