HIV/AIDS, Tuberculosis, Malaria & Neglected Tropical Diseases Cluster, World Health Organization, Geneva, Switzerland.
Indian J Med Res. 2012 May;135(5):737-44.
BACKGROUND & OBJECTIVES: New diagnostic tests for tuberculosis, especially those based on nucleic acid amplification, offer the possibility of early and accurate diagnosis of active TB. In this study we use mathematical modelling to explore the potential epidemiological impact of these new tests, with particular reference to India.
A behavioural model of patient-doctor interactions embedded in an epidemiological model of Mycobacterium tuberculosis transmission, linked to field data, was used to investigate the effects of early diagnosis in preventing future TB cases.
New diagnostic tests for active TB will have a bigger impact sooner where: disease incidence is high and most cases are due to recent infection; advances in test technology (test sensitivity, specificity, etc.) are combined with early diagnosis; new tests have not only better technical specifications than current tests, but also compensate for the misuse of existing tests; health system delays are long compared with patient delays, assuming the former are more amenable to change.
INTERPRETATION & CONCLUSIONS: New diagnostic tests will certainly improve TB control, but the highest impact will be obtained by applying tests with higher sensitivity and specificity early in the infectious period. Refined behavioural and epidemiological models should be able to investigate the mechanisms by which early diagnosis could be achieved, in addition to the consequent epidemiological effects.
新的结核病诊断检测方法，特别是基于核酸扩增的检测方法，为早期、准确诊断活动性结核病提供了可能。本研究采用数学模型，针对印度的情况，探索了这些新检测方法的潜在流行病学影响。
将嵌入于结核分枝杆菌传播的流行病学模型中的患者-医生行为模型与现场数据相连接，用于研究早期诊断对预防未来结核病病例的影响。
新的活动性结核病诊断检测方法将在以下情况下更早地产生更大的影响：疾病发病率高，大多数病例归因于近期感染；检测技术（检测灵敏度、特异性等）的进步与早期诊断相结合；新检测方法不仅具有优于现有检测方法的技术特性，而且还能弥补现有检测方法的误用；与患者的延迟相比，卫生系统的延迟较长，假设前者更容易改变。
新的诊断检测方法肯定会改善结核病控制，但通过在传染性早期应用具有更高灵敏度和特异性的检测方法，将获得最大的影响。除了后续的流行病学影响外，经过改进的行为和流行病学模型还应该能够研究早期诊断的实现机制。
