Department of Clinical Laboratory Diagnosis, Srebrnjak Children's Hospital, Zagreb, Srebrnjak, Zagreb, Croatia.
Arch Med Res. 2011 Feb;42(2):138-43. doi: 10.1016/j.arcmed.2011.02.001.
QuantiFERON-TB Gold In-Tube (QFT-IT) assay is a highly sensitive and specific test for the diagnosis of latent tuberculosis infection. Data on the use of QFT-IT assay in children are scarce and contradictory. The aim of the study was to assess the rate of indeterminate test results and to identify factors contributing to indeterminate results on routine use of QFT-IT assay in nonimmunosuppressed children.
This retrospective study included 2173 children with ages ranging from 1 month to 18 years. Determination of interferon-gamma (IFN-γ) in peripheral blood was performed by commercial QFT-IT assay.
Indeterminate test results were recorded in ten (0.46%) subjects with ages ranging from 15 months to 15 years. The value of negative control was >8.0 kIU/L in one subject, whereas in the remaining nine subjects indeterminate results were consequential to positive control (<0.50 kIU/L). None of these subjects had any history data on congenital or acquired immunodeficiency disorders. Bacterial infection (with elevated body temperature and therapy with β-lactam antibiotics) was present in eight subjects with indeterminate results, one subject had exacerbation of asthma (therapy with inhalation corticosteroids), and one subject was clinically healthy. Repeat IFN-γ determination performed in seven subjects did not yield indeterminate results.
Study results showed the rate of indeterminate QFT-IT results in nonimmunosuppressed children of all age groups to be very low. QFT-IT should preferably be performed upon resolution of acute inflammation in order to avoid repeat testing of indeterminate results in a new blood sample and to reduce the cost of testing.
QuantiFERON-TB Gold In-Tube（QFT-IT）检测法是一种高度敏感和特异的检测方法，可用于诊断潜伏性结核感染。关于 QFT-IT 检测法在儿童中的应用的数据稀缺且相互矛盾。本研究旨在评估不确定检测结果的发生率，并确定导致非免疫抑制儿童常规使用 QFT-IT 检测法时出现不确定结果的因素。
本回顾性研究纳入了年龄在 1 个月至 18 岁之间的 2173 名儿童。通过商业 QFT-IT 检测法检测外周血中干扰素-γ（IFN-γ）的水平。
10 名（0.46%）年龄在 15 个月至 15 岁的儿童出现了不确定的检测结果。一名儿童的阴性对照值>8.0 kIU/L，而其余 9 名儿童的不确定结果是由于阳性对照值<0.50 kIU/L 所致。这些儿童均无先天性或获得性免疫缺陷疾病的病史数据。8 名具有不确定结果的儿童存在细菌感染（伴有发热和β-内酰胺类抗生素治疗），1 名儿童哮喘加重（吸入皮质类固醇治疗），1 名儿童临床健康。对 7 名具有不确定结果的儿童进行的重复 IFN-γ测定未得出不确定结果。
研究结果表明，所有年龄段的非免疫抑制儿童中 QFT-IT 不确定结果的发生率非常低。为避免在新的血样中重复检测不确定结果并降低检测成本，QFT-IT 检测法最好在急性炎症消退后进行。
