The "new" data presented by Drs. Hwang and Wong can be readily obtained from Table 3 of our original publication (1) and are therefore not a revelation. Although our more recent study actually focused on OC and not VC performance, I would nonetheless like to respond to Drs. Hwang and Wong's comments about the positive predictive value of VC. It is important to note that these numbers reflect only adenomatous polyps. Since neither VC nor OC is specific for polyp histology, perhaps it is unfair to count nonadenomatous lesions (such as hyperplastic polyps) as false-positive results. By applying the same logic, the positive predictive values of OC at 10- and 6-mm thresholds were 66.7% (48 of 72) and 65.9% (168 of 255), respectively. This lack of specificity for OC is often overlooked, but in our study, OC-detected "lesions" as large as 8 cm corresponded to normal mucosa (3). When all polyps are considered positive results, regardless of histology, the positive predictive value for VC increases by about 20% (67.4% [62 of 92] and 58.5% [214 of 366] at the 10- and 6-mm thresholds, respectively). Furthermore, because OC is an imperfect reference standard (even with segmental unblinding), it is likely that additional "false-positive" results on VC actually represent false-negative results on OC. It should be understood that a relatively low positive predictive value and high negative predictive value are expected when evaluating a test in a low-prevalence setting, despite excellent sensitivity and specificity. Although the performance of VC in our screening trial was very encouraging, this rapidly evolving technology will no doubt continue to improve. Recent VC software advances and refinement of our colon preparation now allow more rapid and probably more accurate interpretation (4). Because of our proven methods, the VC program at the University of Wisconsin recently became the first to receive widespread reimbursement for VC screening from third-party payers (5). Initial experience with our first 400 patients indicates that the continued improvements are paying off: The positive predictive values are 83.3% for adenomas 10 mm or greater to date (100% for all lesions 10 mm) and 66.7% for adenomas 6 mm or greater (90.5% for all lesions 6 mm). Only 5% of all patients who had VC have been referred for same-day OC, in part because we offer patients with lesions 6 to 9 mm the option of noninvasive VC surveillance. This referral rate bodes well for cost-effectiveness. Finally, with regard to the relative advantages and disadvantages of VC versus OC, I argue that the latter incurs more expense, discomfort, and risk.