title: Operational implementation of LED fluorescence microscopy in screening tuberculosis suspects in an urban HIV clinic in Uganda.
abstract: BACKGROUND
  Light emitting diode (LED) fluorescence microscopy (FM) is an affordable, technology targeted for use in resource-limited settings and recommended for widespread roll-out by the World Health Organization (WHO). We sought to compare the operational performance of three LED FM methods compared to light microscopy in a cohort of HIV-positive tuberculosis (TB) suspects at an urban clinic in a high TB burden country.
  
  
  METHODS
  Two spot specimens collected from TB suspects were included in the study. Smears were stained using auramine O method and read after blinding by three LED-based FM methods by trained laboratory technicians in the Infectious Diseases Institutelaboratory. Leftover portions of the refrigerated sputum specimens were transported to the FIND Tuberculosis Research Laboratory for Ziehl Neelsen (ZN) smear preparation and reading by experienced technologist as well as liquid and solid culture.
  
  
  RESULTS
  174 of 627 (27.8%) specimens collected yielded one or more positive mycobacterial cultures. 94.3% (164/174) were M. tuberculosis complex. LED FM was between 7.3-11.0% more sensitive compared to ZN microscopy. Of the 592 specimens examined by all microscopy methods, there was no significant difference in sensitivity between the three LED FM methods. The specificity of the LED FM methods was between 6.1% and 7.7% lower than ZN microscopy (P<0.001), although exclusion of the single poor reader resulted in over 98% specificity for all FM methods.
  
  
  CONCLUSIONS
  Laboratory technicians in routine settings can be trained to use FM which is more sensitive than ZN microscopy. Despite rigorous proficiency testing, there were operator-dependent accuracy issues which highlight the critical need for intensive quality assurance procedures during LED FM implementation. The low sensitivity of FM for HIV-positive individuals particularly those with low CD4 T cell counts, will limit the number of additional patients found by LED FM in countries with high rates of HIV co-infection.
authors.affiliation: Foundation for Innovative New Diagnostics (FIND), Kampala, Uganda.
authors.forename: Heidi
authors.initials: H
authors.lastname: Albert
authors.forename: Lydia
authors.initials: L
authors.lastname: Nakiyingi
authors.forename: Joseph
authors.initials: J
authors.lastname: Sempa
authors.forename: Olive
authors.initials: O
authors.lastname: Mbabazi
authors.forename: Sheena
authors.initials: S
authors.lastname: Mukkada
authors.forename: Barnabas
authors.initials: B
authors.lastname: Nyesiga
authors.forename: Mark D
authors.initials: MD
authors.lastname: Perkins
authors.forename: Yukari C
authors.initials: YC
authors.lastname: Manabe
mesh_terms: D000328:Adult; D000554:Ambulatory Care Facilities; D015331:Cohort Studies; D005189:False Positive Reactions; D005260:Female; D015658:HIV Infections / Q000150:complications*; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008856:Microscopy, Fluorescence; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000382:microbiology; D014454:Uganda; D014505:Urban Population
references.citation: Scand J Respir Dis. 1966;47(2):114-20
references.pmid: 4161476
references.citation: PLoS One. 2010 Dec 28;5(12):e15206
references.pmid: 21203398
references.citation: Int J Tuberc Lung Dis. 2008 Sep;12(9):1009-14
references.pmid: 18713497
references.citation: Int J Tuberc Lung Dis. 2009 Jul;13(7):836-41
references.pmid: 19555532
references.citation: Eur Respir J. 2011 Dec;38(6):1393-7
references.pmid: 21659413
references.citation: Int J Tuberc Lung Dis. 2006 Sep;10(9):1060-2
references.pmid: 16964802
references.citation: J Acquir Immune Defic Syndr. 2012 Jun 1;60(2):e29-35
references.pmid: 22395671
references.citation: PLoS One. 2010 May 07;5(5):e10527
references.pmid: 20479873
references.citation: Clin Infect Dis. 2008 Jul 15;47(2):203-7
references.pmid: 18532893
references.citation: PLoS One. 2011;6(11):e27125
references.pmid: 22073271
references.citation: Lancet Infect Dis. 2006 Oct;6(10):664-74
references.pmid: 17008175
references.citation: Lancet Infect Dis. 2012 Mar;12(3):201-9
references.pmid: 22015305
references.citation: Int J Tuberc Lung Dis. 2010 Feb;14(2):160-4
references.pmid: 20074406
references.citation: PLoS One. 2011;6(7):e22495
references.pmid: 21811622
references.citation: Eur Respir J. 2012 Nov;40(5):1211-20
references.pmid: 22362849
references.citation: Lancet. 2011 Apr 30;377(9776):1495-505
references.pmid: 21507477
references.citation: BMC Public Health. 2012 Aug 20;12:674
references.pmid: 22905704