BACKGROUND: Fluorescence microscopy offers well-described benefits, compared with conventional light microscopy, for the evaluation of sputum smear samples for tuberculosis. However, its use in resource-limited settings has been limited by the high cost of the excitatory light source. We evaluated the diagnostic performance of fluorescence microscopy, using novel light-emitting diode (LED) technology as an alternative to the conventional mercury vapor lamp (MVP). METHODS: Routinely collected sputum specimens from persons suspected to have tuberculosis who attended community clinics were stained with auramine O and were evaluated using 2 different excitatory light sources (MVP and LED); these specimens were then Ziehl-Neelsen stained and reexamined using light microscopy. Two microscopists independently evaluated all smears. Bacterial culture provided the gold standard. RESULTS: Of the 221 sputum specimens evaluated, 36 (16.3%) were positive for Mycobacterium tuberculosis by culture. Sensitivity and specificity documented for the different modalities were 84.7% and 98.9%, respectively, for the LED assessment; 73.6% and 99.8%, respectively, for the MVP assessment; and 61.1% and 98.9%, respectively, for light microscopy. kappa values for interreader variation were 0.87 for the LED assessment, 0.79 for the MVP assessment, and 0.77 for light microscopy. The mean time to read a negative smear was 1.4 min with fluorescence microscopy and 3.6 min with light microscopy, reflecting a time savings of 61% with fluorescence microscopy. CONCLUSION: LED fluorescence microscopy provides a reliable alternative to conventional methods and has many favorable attributes that facilitate improved, decentralized, diagnostic services.
BACKGROUND: Fluorescence microscopy offers well-described benefits, compared with conventional light microscopy, for the evaluation of sputum smear samples for tuberculosis. However, its use in resource-limited settings has been limited by the high cost of the excitatory light source. We evaluated the diagnostic performance of fluorescence microscopy, using novel light-emitting diode (LED) technology as an alternative to the conventional mercury vapor lamp (MVP). METHODS: Routinely collected sputum specimens from persons suspected to have tuberculosis who attended community clinics were stained with auramine O and were evaluated using 2 different excitatory light sources (MVP and LED); these specimens were then Ziehl-Neelsen stained and reexamined using light microscopy. Two microscopists independently evaluated all smears. Bacterial culture provided the gold standard. RESULTS: Of the 221 sputum specimens evaluated, 36 (16.3%) were positive for Mycobacterium tuberculosis by culture. Sensitivity and specificity documented for the different modalities were 84.7% and 98.9%, respectively, for the LED assessment; 73.6% and 99.8%, respectively, for the MVP assessment; and 61.1% and 98.9%, respectively, for light microscopy. kappa values for interreader variation were 0.87 for the LED assessment, 0.79 for the MVP assessment, and 0.77 for light microscopy. The mean time to read a negative smear was 1.4 min with fluorescence microscopy and 3.6 min with light microscopy, reflecting a time savings of 61% with fluorescence microscopy. CONCLUSION: LED fluorescence microscopy provides a reliable alternative to conventional methods and has many favorable attributes that facilitate improved, decentralized, diagnostic services.
Authors: Yvonne R Shea; J Lucian Davis; Laurence Huang; Joseph A Kovacs; Henry Masur; Francis Mulindwa; Sally Opus; Yuenwah Chow; Patrick R Murray Journal: J Clin Microbiol Date: 2009-03-18 Impact factor: 5.948
Authors: C Bernard; C Wichlacz; M Rigoreau; S Sorhouet; R Dagiral; V Jarlier; N Veziris Journal: J Clin Microbiol Date: 2013-07-24 Impact factor: 5.948
Authors: Ted Cohen; Megan Murray; Kristina Wallengren; Gonzalo G Alvarez; Elizabeth Y Samuel; Douglas Wilson Journal: PLoS Med Date: 2010-06-22 Impact factor: 11.069
Authors: Guang Xue He; Yan Guang Xie; Li Xia Wang; Martien W Borgdorff; Marieke J van der Werf; Ji Huan Fan; Xing Lu Yan; Fa Bin Li; Xue Zhi Zhang; Yan Lin Zhao; Susan van den Hof Journal: PLoS One Date: 2010-05-24 Impact factor: 3.240
Authors: J Lucian Davis; William Worodria; Harriet Kisembo; John Z Metcalfe; Adithya Cattamanchi; Michael Kawooya; Rachel Kyeyune; Saskia den Boon; Krista Powell; Richard Okello; Samuel Yoo; Laurence Huang Journal: PLoS One Date: 2010-03-26 Impact factor: 3.240
Authors: Andrew Ramsay; Luis E Cuevas; Catherine J F Mundy; Carl-Michael Nathanson; Petros Chirambo; Russell Dacombe; S Bertel Squire; Felix M L Salaniponi; Sera Munthali Journal: PLoS One Date: 2009-11-10 Impact factor: 3.240