Imaz María, Allassia Sonia, Aranibar Mónica, Gunia Alba, Poggi Susana, Togneri Ana, Wolff Lidia, Of Fluorescence Group Of Implementation
Instituto Nacional de Enfermedades Respiratorias "Emilio Coni", ANLIS "C.G. Malbrán", Santa Fe, Argentina.
Biomedica. 2017 Jun 1;37(2):164-174. doi: 10.7705/biomedica.v37i2.3276.
Light-emitting diode fluorescence microscopy (LED-FM) has been endorsed by the World Health Organization (WHO) for tuberculosis diagnosis, but its accuracy in HIV-infected patients remains controversial, and only some few studies have explored procedural factors that may affect its performance.
To evaluate the performance of LED-FM for tuberculosis diagnosis in patients with and without HIV infection using a newer, less expensive LED lamp.
We compared the performance of LED-FM and Ziehl-Neelsen (ZN) microscopy on respiratory specimen smears from tuberculosis (TB) suspects and patients on treatment examined by different technicians blinded for HIV-status and for the result of the comparative test. We analyzed the effect of concentrating specimens prior to microscopy using different examination schemes and user-appraisal of the LED device.
Of the 6,968 diagnostic specimens collected, 869 (12.5%) had positive Mycobacterium tuberculosis cultures. LED-FM was 11.4% more sensitive than ZN (p;0.01). Among HIV-positive TB patients, sensitivity differences between LED-FM and ZN (20.6%) doubled the figure obtained in HIVnegative patients or in those with unknown HIV status (9.3%). After stratifying by direct and concentrated slides, the superiority of LED-FM remained. High specificity values were obtained both with LED-FM(99.9%) and ZN (99.9%).The second reading of a sample of slides showed a significantly higher positive detection yield using 200x magnification (49.4 %) than 400x magnification (33.8%) (p;0.05). The LEDdevice had a very good acceptance among the technicians.
LED-FM better performance compared with ZN in HIV-infected patients and user-appraisal support the rapid roll-out of LED-FM. Screening at 200x magnification was essential to achieve LEDFM increased sensitivity.
发光二极管荧光显微镜（LED-FM）已得到世界卫生组织（WHO）认可用于结核病诊断，但其在HIV感染患者中的准确性仍存在争议，仅有少数研究探讨了可能影响其性能的操作因素。
使用一种更新、成本更低的LED灯，评估LED-FM在HIV感染和未感染患者中诊断结核病的性能。
我们比较了LED-FM和萋-尼（ZN）显微镜对结核病（TB）疑似患者及接受治疗患者的呼吸道标本涂片的检测性能，这些标本由对HIV状态和对比检测结果不知情的不同技术人员进行检查。我们分析了在显微镜检查前采用不同检查方案浓缩标本的效果以及用户对LED设备的评价。
在收集的6968份诊断标本中，869份（12.5%）结核分枝杆菌培养呈阳性。LED-FM的敏感性比ZN高11.4%（p<0.01）。在HIV阳性的TB患者中，LED-FM和ZN之间的敏感性差异（20.6%）是HIV阴性患者或HIV状态未知患者（9.3%）的两倍。按直接涂片和浓缩涂片分层后，LED-FM的优势依然存在。LED-FM（99.9%）和ZN（99.9%）均获得了较高的特异性值。对一组涂片样本进行二次读数显示，使用200倍放大倍数时的阳性检出率（49.4%）显著高于400倍放大倍数时（33.8%）（p<0.05）。该LED设备在技术人员中获得了很高的认可度。
与ZN相比，LED-FM在HIV感染患者中表现更优，且用户评价支持LED-FM的快速推广。200倍放大倍数筛查对于提高LED-FM的敏感性至关重要。
