Fluorescence microscopy for tuberculosis diagnosis

Hùng, Nguyễn Văn; Sy, Dinh Ngoc; Anthony, Richard; Cobelens, Frank; Soolingen, Dick van

doi:10.1016/s1473-3099(07)70059-2

Cited by 27 publications

(11 citation statements)

References 2 publications

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“…[6] showed a slightly better, although not statistically significant, detection rate using LED as compared with MVFM (5 versus 12%, n=221), while Van Hung et al . [16] reported slightly lower sensitivity of LED microscopy, which they attributed to photo-bleaching, as the smears were read on a MVL microscope before the LED microscope. However, there are hardly any data for HIV–TB-co-infected persons and the published WHO guideline does not address performance in this subgroup of patients, although WHO recommendations are meant apply to both HIV-infected and non-HIV-infected TB suspects.…”

Section: Discussionmentioning

confidence: 99%

Comparative cost and performance of light-emitting diode microscopy in HIV–tuberculosis-co-infected patients

et al. 2011

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Light-emitting diode (LED) microscopy has recently been endorsed by the World Health Organization (WHO). However, it is unclear whether LED is as accurate and cost-effective as Ziehl–Neelsen (ZN) microscopy or mercury vapour fluorescence microscopy (MVFM) in tuberculosis (TB)–HIV-co-infected subjects. Direct and concentrated sputum smears from TB suspects were evaluated using combinations of LED microscopy, ZN microscopy and MVFM. Median reading time per slide was recorded and a cost analysis performed. Mycobacterial culture served as the reference standard. 647 sputum samples were obtained from 354 patients (88 (29.8%) were HIV-infected and 161 (26%) were culture-positive for Mycobacterium tuberculosis). Although overall sensitivity of LED compared with ZN microscopy or MVFM was similar, sensitivity of all three modalities was lower in HIV-infected patients. In the HIV-infected group, the sensitivity of LED microscopy was higher than ZN microscopy using samples that were not concentrated (46 versus 39%; p=0.25), and better than MVFM using concentrated samples (56 versus 44; p=0.5). A similar trend was seen in the CD4 count <200 cells mL−1 subgroup. Median (interquartile range) reading time was quicker with LED compared with ZN microscopy (1.8 (1.7–1.9) versus 2.5 (2.2–2.7) min; p ≤0.001). Average cost per slide read was less for LED microscopy (US$1.63) compared with ZN microscopy (US$2.10). Among HIV–TB-co-infected patients, LED microscopy was cheaper and performed as well as ZN microscopy or MVFM independent of the staining (ZN or auramine O) or processing methods used.

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Section: Discussionmentioning

confidence: 99%

Comparative cost and performance of light-emitting diode microscopy in HIV–tuberculosis-co-infected patients

et al. 2011

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“…Power consumption is much lower, to the point where portable battery operation or solar power is feasible. Finally, it has been reported that image quality remains good outside of a darkroom [16], a significant advantage where space constraints and lack of air conditioning are important barriers to user acceptance. Table 1 shows the major commercial LED products that are currently marketed for direct detection of TB:…”

Section: Light-emitting Diode Technologies For Tb Diagnosis: What Is mentioning

confidence: 99%

“…In a letter published in Lancet Infectious Disease, Van Hung et al described using a similarly adapted microscope for examination of auramine O-stained patient specimens in parallel with blinded examination using a conventional MV microscope [16]. They reported good concordance between these two readings (98%; k: 0.93) and confirmed user-favorable qualities, such as the lack of heat produced by the light source and the ability to perform readings without a completely darkened room [16]. [10,19].…”

Section: Current Literaturementioning

confidence: 99%

Light-emitting diode technologies for TB diagnosis: what is on the market?

Minion

Sohn

Pai

2009

Expert Review of Medical Devices

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“…Studies conducted in reference laboratory settings, showed LED FMs to have an average of 10% greater sensitivity than light microscopy and similar specificity [13], [14], [15]. LED fluorescent microscopes are inexpensive, use cheap and affordable bulbs with life spans greater than 10,000 hours; can run on batteries and do not require a dark room [16], [17], [18], [19], [20], [21], [22]. In addition, studies have found that LED FMs have 2–4 times faster examination time per slide [14], [23], [24].…”

Section: Introductionmentioning

confidence: 99%

“…To date the majority of LED FM literature focuses on validation studies conducted in reference laboratories using laboratory technicians who are well-trained and experienced in fluorescent microscopy [14], [19], [20], [26]. As a next step, WHO recommends country-specific adaptation and validation of LED FMs.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2011

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The World Health Organization recommends the roll-out of light-emitting diode (LED) fluorescent microscopes (FM) as an alternative to light microscopes in resource-limited settings. We evaluated the acceptability and performance of three LED FMs after a short orientation among laboratory technicians from government health centers in Zambia. Sixteen technicians with varied light microscopy experience were oriented to FMs and divided into groups; each group read a different set of 40 slides on each LED FM (Primo Star iLED™, Lumin™, FluoLED™) and on a reference mercury-vapor FM (Olympus BX41TF). Slide reading times were recorded. An experienced FM technician examined each slide on the Olympus BX41TF. Sensitivity and specificity compared to TB culture were calculated. Misclassification compared to the experienced technician and inter-rater reliability between trainees was assessed. Trainees rated microscopes on technical aspects. Primo Star iLED™, FluoLED™ and Olympus BX41TF had comparable sensitivities (67%, 65% and 65% respectively), with the Lumin™ significantly worse (56%; p<0.05). Specificity was low for trainees on all microscopes (75.9%) compared to the experienced technician on Olympus BX41TF (100%). Primo Star iLED™ had significantly less misclassification (21.1% p<0.05) than FluoLED™ (26.5%) and Lumin™ (26.8%) and significantly higher inter-rater reliability (0.611; p<0.05), compared to FluoLED™ (0.523) and Lumin™ (0.492). Slide reading times for LED FMs were slower than the reference, but not significantly different from each other. Primo Star iLED™ rated highest in acceptability measures, followed by FluoLED™ then Lumin™. Primo Star iLED™ was consistently better than FluoLED™ and Lumin™, and performed comparably to the Olympus BX41TF in all analyses, except reading times. The Lumin™ compared least favorably and was thought unacceptable for use. Specificity and inter-rater reliability were low for all microscopes suggesting that a brief orientation was insufficient in this setting. These results provide important data for resource-limited settings to consider as they scale-up LED FMs.

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Fluorescence microscopy for tuberculosis diagnosis

Cited by 27 publications

References 2 publications

Comparative cost and performance of light-emitting diode microscopy in HIV–tuberculosis-co-infected patients

Comparative cost and performance of light-emitting diode microscopy in HIV–tuberculosis-co-infected patients

Light-emitting diode technologies for TB diagnosis: what is on the market?

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

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