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Updated: Apr 3, 2026

Optical Scatter Microscopy Based on Two-Dimensional Gabor Filters
Published on: June 2, 2010
Is bleach-sedimented smear microscopy an alternative to direct microscopy under programme conditions in India?
P H Vishnu1, P Bhat2, A Bansal2
1State Tuberculosis Training and Demonstration Centre, Hyderabad, Andra Pradesh, India.
Abstract:
This cross-sectional multi-centric study compared the yield of and potential benefit for detecting smear-positive pulmonary tuberculosis (PTB) by bleach sedimentation (2% sodium-hypochlorite) versus direct microscopy under programme conditions in India. Among 3168 PTB suspects, 684 (21.6%) were detected by bleach sedimentation vs. 625 (19.7%) by direct microscopy, with a proportional overall agreement of 96% (κ = 0.88). While 594 patients were smear-positive with both methods, 31 patients detected by direct microscopy were missed and an additional 90 patients were detected by bleach sedimentation. Overall, bleach sedimentation increased the yield of smear-positive TB detection; however; it also increased the time to results.
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