An Evaluation of the Performance and Acceptability of Three LED Fluorescent Microscopes in Zambia: Lessons Learnt for Scale-Up

Turnbull, Eleanor; Kaunda, Kaunda; Harris, Jennifer B.; Kapata, Nathan; Muvwimi, Mweemba Wilfred.; Krüüner, Annika; Henostroza, German; Reid, Stewart E.

doi:10.1371/journal.pone.0027125

Cited by 12 publications

(8 citation statements)

References 13 publications

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“…These results differ from several previous studies where LED-FM increases an average of 10 % of sensitivity over the conventional ZN technique [6–10]. Other studies have shown equal sensitivity or low specificity of LED-FM compared to conventional ZN technique [9, 11–13]. In these studies, readers had no previous experience with fluorescence microscopy, which is the most likely explanation for sensitivity differences compared with other studies and indicating the importance of adapting training intensity according to the level of operator proficiency.…”

Section: Discussioncontrasting

confidence: 92%

Diagnostic performance of smear microscopy and incremental yield of Xpert in detection of pulmonary tuberculosis in Rwanda

et al. 2016

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BackgroundTuberculosis control program of Rwanda is currently phasing in light emitting diode-fluorescent microscopy (LED-FM) as an alternative to Ziehl-Neelsen (ZN) smear microscopy. This, alongside the newly introduced Xpert (Cepheid, Sunnyvale, CA, USA) is expected to improve diagnosis of tuberculosis and detection of rifampicin resistance in patients at health facilities. We assessed the accuracy of smear microscopy and the incremental sensitivity of Xpert at tuberculosis laboratories in Rwanda.MethodsThis was a cross-sectional study involving four laboratories performing ZN and four laboratories performing LED-FM microscopy. The laboratories include four intermediate (ILs) and four peripheral (PLs) laboratories. After smear microscopy, the left-over of samples, of a single early-morning sputum from 648 participants, were tested using Xpert and mycobacterial culture as a reference standard. Sensitivity of each test was compared and the incremental sensitivity of Xpert after a negative smear was assessed.ResultsA total of 96 presumptive pulmonary tuberculosis participants were culture positive for M. tuberculosis. The overall sensitivity in PL of ZN was 55.1 % (40.2–69.3 %), LED-FM was 37 % (19.4–57.6 %) and Xpert was 77.6 % (66.6–86.4 %) whereas in ILs the same value for ZN was 58.3 % (27.7–84.8 %), LED-FM was 62.5 % (24.5–91.5 %) and Xpert was 90 (68.3–98.8 %). The sensitivity for all tests was significantly higher among HIV-negative individuals (all test p <0.05). The overall incremental sensitivity of Xpert over smear microscopy was 32.3 %; p < 0.0001. The incremental sensitivity of Xpert was statistically significant for both smear methods at PL (32.9 %; p = 0.001) but not at the ILs (30 %; p = 0.125) for both smear methods.ConclusionsOur study findings of the early implementation of the LED-FM did not reveal significant increment in sensitivity compared to the method being phased out (ZN). This study showed a significant incremental sensitivity for Xpert from both smear methods at peripheral centers where majority of TB patients are diagnosed. Overall our findings support the recommendation for Xpert as an initial diagnostic test in adults and children presumed to have TB.

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Section: Discussioncontrasting

confidence: 92%

Diagnostic performance of smear microscopy and incremental yield of Xpert in detection of pulmonary tuberculosis in Rwanda

et al. 2016

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“…Slides should be re-read by experienced technicians with feedback given on discrepant results in real time. Similarly, in Zambia, a high-incidence, resource-limited setting, a study of 16 technicians' proficiency after training which also compared all 3 microscopes showed significant differences among technicians that led to low inter-rater reliability and high misclassification rates that overwhelmed any differences in sensitivity among the LED platforms [14].…”

Section: Discussionmentioning

confidence: 99%

Operational Implementation of LED Fluorescence Microscopy in Screening Tuberculosis Suspects in an Urban HIV Clinic in Uganda

Albert¹,

Nakiyingi

Sempa

et al. 2013

PLoS ONE

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BackgroundLight 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.MethodsTwo 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.Results174 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.ConclusionsLaboratory 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.

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“…Comparative studies showed relatively little difference in accuracy between commercial LED-based products, 23,28,29,36 although the Lumin (LW Scientific) had lower sensitivity in two out of four studies. Overall user appraisal was high across studies; where assessed, the Primo Star iLED (Carl Zeiss Microscopy) ranked highest in terms of user preference, and the Lumin (LW Scientific) ranked lowest.…”

Section: Review Of Who-endorsed Tb Diagnostic Tests 2006-2012 Microsmentioning

confidence: 91%

“…24,26,[29][30][31] These findings were also confirmed for HIVinfected patients. 32,33 However, three studies reported equal sensitivity 34 or lower specificities 30,35,36 for LED FM compared with ZN. In these studies, readers had no previous experience with fluorescence microscopy, which is the most likely explanation for performance differences compared with other studies.…”

Section: Review Of Who-endorsed Tb Diagnostic Tests 2006-2012 Microsmentioning

confidence: 98%

The Changing Landscape of Diagnostic Services for Tuberculosis

Boehme

Saacks

O’Brien

2013

Semin Respir Crit Care Med

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During the last decade there has been a dramatic change in the laboratory approach to tuberculosis (TB) diagnosis in the developing world. This change began with the realization that acid-fast bacillus smear microscopy alone was totally inadequate to deal with the dual problems of human immunodeficiency virus (HIV)-associated TB and drug-resistant TB that threaten to undermine global progress in TB control. Subsequently, increased financial resources for TB laboratory services and the establishment of a systematic process for endorsement of new TB diagnostic tools and approaches by the World Health Organization (WHO) have led to rapid expansion of TB laboratory services and the availability of several new diagnostic tests that have been introduced. These include both commercial automated and noncommercial systems for phenotypic mycobacterial liquid culture and drug susceptibility testing, a simple and inexpensive test for mycobacterial species identification in culture isolates, light-emitting diode fluorescence microscopy, and rapid molecular methods for TB case detection and the diagnosis of drug-resistant TB. The latter methodologies that include line probe assays and an automated cartridge-based real-time polymerase chain reaction (PCR)-based test are being scaled up at an unprecedented pace and are truly revolutionizing the diagnosis of drug-resistant TB. On the other hand, little progress has been made in the quest for a true point-of-care test for TB. Fortunately, this is being addressed in several discovery initiatives that hopefully will provide impetus for the development of rapid, accurate TB diagnostics for the lowest level of the health system.

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An Evaluation of the Performance and Acceptability of Three LED Fluorescent Microscopes in Zambia: Lessons Learnt for Scale-Up

Cited by 12 publications

References 13 publications

Diagnostic performance of smear microscopy and incremental yield of Xpert in detection of pulmonary tuberculosis in Rwanda

Diagnostic performance of smear microscopy and incremental yield of Xpert in detection of pulmonary tuberculosis in Rwanda

Operational Implementation of LED Fluorescence Microscopy in Screening Tuberculosis Suspects in an Urban HIV Clinic in Uganda

The Changing Landscape of Diagnostic Services for Tuberculosis

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