Health Research Unit, Faculty of Medicine, Universitas Padjadjaran/Hasan Sadikin Hospital, Bandung, Indonesia.
PLoS One. 2013 Apr 19;8(4):e61727. doi: 10.1371/journal.pone.0061727. Print 2013.
Fluorescence 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.
We 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.
Among 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.
High 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.
荧光显微镜（FM）在结核病流行地区尚未广泛应用，对 HIV 感染者的评估也很少。我们在印度尼西亚的一家医院（该医院是 HIV 感染者的转诊中心）评估了基于发光二极管技术（LED-FM）的 FM 与传统（Zieh-Neelsen）显微镜相比的诊断性能、时间和成本，该医院对疑似肺结核患者进行了研究。
我们纳入了门诊和 HIV 诊所的疑似肺结核患者。两名技术员对直接和浓缩痰液涂片使用 LED-FM 和 ZN 显微镜进行检查，他们对 HIV 状态和比较试验的结果均不知情。记录每张载玻片的平均阅读时间，并计算每张载玻片的成本。分枝杆菌培养作为参考标准。
在来自门诊的 404 例和来自 HIV 诊所的 256 例疑似肺结核患者中，分枝杆菌培养阳性率分别为 12.6%和 27%。使用≥2 AFB/长度的阈值，LED-FM 的最佳灵敏度。与 ZN 显微镜相比，LED-FM 的灵敏度更高（75.5%比 54.9%，P<0.01），但特异性较低（90.0%比 96.6%，P<0.01）。HIV 与较低的灵敏度相关，但特异性相似。使用 LED-FM 的平均阅读时间明显缩短（2.23±0.78 比 5.82±1.60 分钟，P<0.01），而每张载玻片的成本相似。
LED-FM 的高灵敏度与痰涂片载玻片的较短阅读时间相结合，使该方法成为 ZN 显微镜的潜在替代方法。需要更多关于特异性的额外数据，以便在高负担的结核病实验室中有效实施该技术。
