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大型城市环境中核酸扩增试验在结核病诊断中的性能

Performance of nucleic acid amplification tests for diagnosis of tuberculosis in a large urban setting.

作者信息

Laraque Fabienne, Griggs Anne, Slopen Meredith, Munsiff Sonal S

机构信息

Bureau of Tuberculosis Control, New York City Department of Health of Mental Hygiene, New York 10013, USA.

出版信息

Clin Infect Dis. 2009 Jul 1;49(1):46-54. doi: 10.1086/599037.

DOI:10.1086/599037

PMID:19476429

Abstract

BACKGROUND

A diagnosis of tuberculosis (TB) relies on acid-fast bacilli (AFB) smear and culture results. Two rapid tests that use nucleic acid amplification (NAA) have been approved by the US Food and Drug Administration for the diagnosis of TB based on detection of Mycobacterium tuberculosis from specimens obtained from the respiratory tract. We evaluated the performance of NAA testing under field conditions in a large urban setting with moderate TB prevalence.

METHODS

The medical records of patients with suspected TB during 2000-2004 were reviewed. Analysis was restricted to the performance of NAA on specimens collected within 7 days after the initiation of treatment for TB. The assay's sensitivity, specificity, and positive and negative predictive values (PPV and NPV, respectively) were evaluated.

RESULTS

The proportion of patients with confirmed or suspected TB whose respiratory tract specimens were tested by use of NAA increased from 429 (12.9%) of 3334 patients in 2000 to 527 (15.6%) of 3386 patients in 2004; NAA testing among patients whose respiratory tract specimens tested positive for AFB increased from 415 (43.6%) of 952 patients in 2000 to 487 (55.5%) of 877 patients in 2004 (P < .001 for both trends). Of the 16,511 patients being evaluated for pulmonary TB, 4642 (28.1%) had specimens that tested positive for AFB on smear. Of those 4642 patients, 2241 (48.3%) had NAA performed on their specimens. Of those 2241 patients, 1279 (57.1%) had positive test results. Of those 1279 patients, 1262 (98.7%) were confirmed to have TB. For 1861 (40.1%) of the 4642 patients whose specimens tested positive for AFB on smear, the NAA test had a sensitivity of 96.0%, a specificity of 95.3%, a PPV of 98.0%, and an NPV of 90.9%. For 158 patients whose specimens tested negative for AFB on smear, the NAA test had a sensitivity of 79.3%, a specificity of 80.3%, a PPV of 83.1%, and an NPV of 76.0%, respectively. For the 215 specimens that tested positive for AFB by smear, we found a sensitivity, specificity, PPV, and NPV of 97.5%, 93.6%, 95.1%, and 96.8%, respectively. A high-grade smear was associated with a better test performance.

CONCLUSION

NAA testing was helpful for determining whether patients whose specimens tested positive for AFB on smear had TB or not. This conclusion supports the use of this test for early diagnosis of pulmonary and extrapulmonary TB.

摘要

背景

结核病（TB）的诊断依赖于抗酸杆菌（AFB）涂片和培养结果。美国食品药品监督管理局已批准两种使用核酸扩增（NAA）的快速检测方法，用于基于从呼吸道获取的标本中检测结核分枝杆菌来诊断结核病。我们在结核病患病率中等的大型城市环境中评估了现场条件下NAA检测的性能。

方法

回顾了2000 - 2004年疑似结核病患者的病历。分析仅限于对结核病治疗开始后7天内采集的标本进行NAA检测的性能。评估了该检测方法的敏感性、特异性以及阳性和阴性预测值（分别为PPV和NPV）。

结果

呼吸道标本接受NAA检测的确诊或疑似结核病患者比例从2000年3334例患者中的429例（12.9%）增至2004年3386例患者中的527例（15.6%）；呼吸道标本AFB检测呈阳性的患者中，NAA检测从2000年952例患者中的415例（43.6%）增至2004年877例患者中的487例（55.5%）（两种趋势的P均<0.001）。在接受肺结核评估的16511例患者中，4642例（28.1%）的标本涂片AFB检测呈阳性。在这4642例患者中，2241例（48.3%）的标本进行了NAA检测。在这2241例患者中，1279例（57.1%）检测结果为阳性。在这1279例患者中，1262例（98.7%）被确诊患有结核病。对于涂片AFB检测呈阳性的4642例患者中的1861例（40.1%），NAA检测的敏感性为96.0%，特异性为95.3%，PPV为98.0%，NPV为90.9%。对于涂片AFB检测呈阴性的158例患者，NAA检测的敏感性分别为79.3%，特异性为80.3%，PPV为83.1%，NPV为76.0%。对于涂片AFB检测呈阳性的215份标本，我们发现敏感性、特异性、PPV和NPV分别为97.5%、93.6%、95.1%和96.8%。高等级涂片与更好的检测性能相关。