Pediatr Infect Dis J. 2018 Apr;37(4):292-297. doi: 10.1097/INF.0000000000001792.
The T-SPOT.TB, an interferon-gamma release assay, is an indirect test of Mycobacterium tuberculosis infection. Due to sparse and conflicting evidence, the use of interferon-gamma release assay is limited in young and HIV-infected children. We determined the prevalence of invalid, borderline, positive and negative results and associations with key demographic variables during routine pediatric use in a low tuberculosis burden setting.
For pediatric samples received at Oxford Diagnostic Laboratories between 2010 and 2015, the associations between initial test outcome and demographics were estimated by bivariate analysis and logistic regression.
A total of 44,289 samples (median age 12.5 years; interquartile range 7.7-15.5), including 5057 samples (11.6%) from children under 5 years old, were received from 46 U.S. states, Washington, DC and Puerto Rico. A total of 592 samples (1.3%) could not be tested. T-SPOT.TB positivity was strongly correlated (r = 0.60; P < 0.0001) with state TB incidence. Compared with negative results, positive results were more likely in samples from older children (P < 0.0001), public health clinics (P < 0.0001) and rural locations (P = 0.005). Although infrequent (0.6%), invalid results were more common in samples collected at HIV clinics (odds ratio = 2.5, 95% confidence interval: 1.3-4.9) and from younger children (P = 0.03). These invalid results were more likely due to a robust nil (negative) control response rather than a weak mitogen (positive) control response.
The T-SPOT.TB test correlated strongly with well-recognized risk factors for tuberculosis infection and provided evaluable results in 98% of children. To optimize the impact of testing on clinical decision making and patient outcomes, local epidemiology and individual patient risk should be considered when incorporating IGRAs into pediatric guidelines.
T-SPOT.TB 是一种干扰素-γ释放检测，是一种间接检测结核分枝杆菌感染的方法。由于证据稀少且存在冲突，干扰素-γ释放检测在年轻和感染 HIV 的儿童中的应用受到限制。我们在低结核负担环境下，确定了常规儿科应用中无效、边界、阳性和阴性结果的流行率，并确定了与关键人口统计学变量的关联。
对于 2010 年至 2015 年期间在牛津诊断实验室收到的儿科样本，通过双变量分析和逻辑回归估计初始检测结果与人口统计学变量之间的关系。
共收到来自美国 46 个州、华盛顿特区和波多黎各的 44289 份样本（中位数年龄为 12.5 岁；四分位距 7.7-15.5），其中 5057 份（11.6%）来自 5 岁以下儿童。共有 592 份（1.3%）样本无法进行检测。T-SPOT.TB 的阳性率与州结核病发病率密切相关（r = 0.60；P < 0.0001）。与阴性结果相比，年龄较大的儿童（P < 0.0001）、公共卫生诊所（P < 0.0001）和农村地区（P = 0.005）的样本更有可能呈阳性。虽然很少见（0.6%），但在 HIV 诊所采集的样本（比值比=2.5，95%置信区间：1.3-4.9）和年龄较小的儿童中，无效结果更为常见（P = 0.03）。这些无效结果更可能是由于强大的阴性（阴性）对照反应而不是较弱的有丝分裂原（阳性）对照反应所致。
T-SPOT.TB 检测与结核感染的公认危险因素密切相关，98%的儿童可获得可评估的结果。为了优化检测对临床决策和患者结局的影响，在将 IGRAs 纳入儿科指南时，应考虑当地的流行病学和个体患者的风险。
