Adequacy of urine cytology specimens: an assessment of collection techniques

The objective of this study was to determine whether the method of urine collection impacts the adequacy and cell counts of cytology specimens in a low-risk population. Voided, post-cystometrogram (CMG), and bladder irrigant specimens were collected and evaluated for cytologic adequacy and average cell count by a single cytopathologist masked to the source of each sample. Data were analyzed to detect differences in specimen adequacy and cell counts based on method of collection. Both the voided and post-CMG specimens (97.3%, 93.7% respectively) were significantly more likely to be adequate compared to the bladder irrigant specimen (11.7%, p < 0.0001). The spontaneously voided specimen (211.4 +/- 100.1) had significantly higher cell counts than both the post-CMG specimen (85.9 +/- 86.6) and the cystoscopy specimen (6.4 +/- 19.6, p < 0.0001). In a multivariate linear model, collection method and specimen adequacy were associated with increased cell count/hpf (p < 0.001), as was the presence of hematuria on urine dipstick (p = 0.03). No cytologic abnormalities were diagnosed. Whereas both spontaneously voided and post-CMG specimens were consistently adequate for interpretation, spontaneous voided specimens were optimal with regard to maximizing cell count/hpf.