Objective: to Measurethe Time Spent During Routine Sputum Smear Microscopy and Assess Whetherre-Examining Slides For 10 Min Translates into Higher Case Detection Ofsmear-Positive Cases. Design: a Prospectiveobservational Study Over A12-Month Period With Three Components: 1) Timing Ofroutine Sputum Smear Examination; 2) Blinded Re-Examination of All Slides For10 Min and Results Compared With Initial Readings; and 3) Blindedre-Examination, By the Original Microscopists, of a Portion of False-Negativeslide Smixed With True Negatives For 10Min. Results: a Total 612Sputum Specimens For Screening. the Routine Examination Time the Median Routineexamination Time Was 5 Min. a 10 Min Examination Significantly Increased Thenumber of Positive Smears from 94 to 131. on Review By the Original Readers,More Than Half of the False-Negative Slides Were Reported As Positive After 10Min. Conclusion: Sputumsmear Microscopy Has Low Sensitivity If Performed Too Quickly, and 10 Minre-Examination Significantly Increases Case Detection. Ensuring That Smears Areexamined For the Recommended Duration May Be a Simple and Low-Cost Way Toimprove Case Detection.