BACKGROUND: Interferon-gamma release assays (IGRAs) are newly approved for diagnosing latent tuberculosis infection (LTBI). An internal audit was conducted to review the use of a newly implemented IGRA at the Hôpital du Sacré-Coeur de Montréal (Montréal, Québec) to evaluate its concordance with Canadian recommendations and its implication on diagnosis.METHODS: From April 2007 to January 2009, all Quantiferon TB Gold In-Tube (QFT, Cellestis inc, USA) tests performed in at the Hôpital du Sacré-Coeur de Montréal were retrieved. Strategies used to investigate LTBI and clinical interpretation of test results were compared with the local algorithm, which is derived from the current national guidelines.RESULTS: A total of 200 patients tested with QFT were included in the analysis. LTBI investigation and QFT testing were considered to be appropriate in 87.5% and 66.5% of patients, respectively. Overall, 67 QFT tests were performed inappropriately; 25 were performed when a LTBI investigation was not indicated and 42 were performed whe LTBI interpretation was possible with the result of the tuberculin skin test alone. Among the 175 patients investigated appropriately for LTBI, 49 QFT tests (28%) were interpreted incorrectly; 32 patients (at high risk of developing active tuberculosis) had a positive tuberculin skin test and a negative QFT result wrongly interpreted as being negative for LTBI and 13 patients should have undergone further LTBI investigations.CONCLUSION: Globally, the present study revealed that there are discrepancies on how the IGRA was employed and interpreted in a Montreal hospital and that strict compliance to the guidelines could significantly reduce errors in interpretation.

中文翻译：

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干扰素γ释放测定的应用和解释：加拿大中心的审计结果。

背景：干扰素-γ释放测定（IGRA）新近被批准用于诊断潜伏性结核感染（LTBI）。我们进行了一次内部审计，以审查蒙特利尔圣心医院（魁北克省蒙特利尔）新实施的 IGRA 的使用情况，以评估其与加拿大建议的一致性及其对诊断的影响。 方法：从 2007 年 4 月到 2009 年 1 月，检索了在蒙特利尔圣心医院进行的所有 Quantiferon TB Gold In-Tube（QFT，Cellestis Inc，美国）测试。将用于调查 LTBI 的策略和测试结果的临床解释与源自当前国家指南的本地算法进行了比较。 结果：分析中纳入了总共 200 名接受 QFT 测试的患者。LTBI 检查和 QFT 测试被认为分别适合 87.5% 和 66.5% 的患者。总体而言，67 项 QFT 测试执行不当；25 项是在未指示进行 LTBI 调查时进行的，42 项是在仅用结核菌素皮试结果就可能解释 LTBI 时进行的。在 175 名患者中进行了 LTBI 适当调查，其中 49 名 QFT 测试 (28%) 被错误解读；32 名患者（发展为活动性结核病的高风险）的结核菌素皮试呈阳性，而 QFT 结果呈阴性，被错误地解释为 LTBI 阴性，其中 13 名患者应接受进一步的 LTBI 检查。 结论：在全球范围内，本研究表明，有蒙特利尔一家医院如何使用和解释 IGRA 存在差异，严格遵守指南可以显着减少解释错误。