Implementation of LED Fluorescence Microscopy for Diagnosis of Pulmonary and HIV-Associated Tuberculosis in a Hospital Setting in Indonesia

Abstract

BackgroundFluorescence microscopy (FM) has not been implemented widely in TB endemic settings and little evaluation has been done in HIV-infected patients. We evaluated diagnostic performance, time and costs of FM with light-emitting diodes technology (LED-FM), compared with conventional (Zieh-Neelsen) microscopy in a hospital in Indonesia which acts as referral centre for HIV-infected patients.MethodWe included pulmonary tuberculosis suspects from the outpatient and HIV clinic. Direct and concentrated sputum smears were examined using LED-FM and ZN microscopy by two technicians who were blinded for the HIV-status and the result of the comparative test. Mean reading time per slide was recorded and cost of each slide was calculated. Mycobacteria culture served as the reference standard.ResultsAmong 404 tuberculosis suspects from the outpatient clinic and 256 from the HIV clinic, mycobacteria culture was positive in 12.6% and 27%, respectively. The optimal sensitivity of LED-FM was achieved by using a threshold of ≥2 AFB/length. LED-FM had a higher sensitivity (75.5% vs. 54.9%, P<0.01) but lower specificity (90.0% vs 96.6%, P<0.01) compared to ZN microscopy. HIV was associated with a lower sensitivity but similar specificity. The average reading time using LED-FM was significantly shorter (2.23±0.78 vs 5.82±1.60 minutes, P<0.01), while costs per slide were similar.ConclusionHigh sensitivity of LED-FM combined with shorter reading time of sputum smear slides make this method a potential alternative to ZN microscopy. Additional data on specificity are needed for effective implementation of this technique in high burden TB laboratories.

Light-emitting diode fluorescence microscopy for tuberculosis diagnosis: a meta-analysis

“…Nonetheless, SROC plots suggested that liquid culture reference standard was associated with higher diagnostic accuracy of LED-FM (see online supplementary material). Studies using culture on one specimen (n=7) [14-17, 19, 22, 23] had a lower pooled specificity (94.7%) and a higher sensitivity (70.0%) compared with studies using more than one specimen (n=6) [13,15,18,20,21,24] (98.5% and 61.1%, respectively), although the differences were not statistically significant. SROC plots suggested that culture reference based on more than one specimen improved the diagnostic accuracy of LED-FM, although associated with increasing heterogeneity in both sensitivity and specificity estimates of the LED-FM (see online supplementary material).…”

“…12 articles [13][14][15][16][17][18][19][20][21][22][23][24], reporting 12 independent studies, were included in the meta-analysis. One study [15] had two different patient groups (group 1: unlikely HIV-infected; group 2: HIV-infected) with separately analysed data. We considered these two patient groups to be independent in the meta-analysis.…”

“…The 12 prospective studies [13][14][15][16][17][18][19][20][21][22][23][24] were conducted across 11 countries and assessed six commercial LED-FM systems (table 1). All studies were located in middle-or low-income countries [25] and 11 recruited sites in WHO-recognised, high-TB-burden countries [1].…”

“…Pooled estimates were not generated for HIV-uninfected patients as there were fewer than four studies. SROC indicated higher diagnostic accuracy of LED-FM from the two study groups [15,16] of HIV-negative patients compared with expansive variability in both sensitivity and specificity estimates among studies with HIV-infected subjects (see online supplementary material).…”

“…Performance evaluations of all the other devices were based on fewer than four studies. Nevertheless, all three evaluations of CyScope® (Partec, Görlitz, Germany) [15,17] reported low performance as compared with the other devices. Pooled performance estimates were only yielded from studies using ×400 magnification [13-15, 18, 20, 22, 23].…”