Gupta D, Saiprakash B V, Aggarwal A N, Muralidhar S, Kumar B, Jindal S K
Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
J Assoc Physicians India. 2001 Mar;49:332-5.
To assess the utility of various cut-off points of tuberculin skin test in making a diagnosis of tuberculosis in patients with respiratory symptoms.
Tuberculin skin test was conducted on consecutive new patients attending chest clinic for various respiratory symptoms. All subjects were then investigated to establish diagnosis, and categorized into tuberculous and nontuberculous groups. Receiver operating characteristic (ROC) curve was plotted to evaluate discrimination by tuberculin skin test. Sensitivity, specificity and predictive value were also calculated at various cut-off points.
Of 250 patients, 59 (23.6%) had tuberculosis on clinical and microbiological criteria (other than the tuberculin test). Sensitivity and specificity of tuberculin test at readings greater than 5, 10 and 15 mm were 0.8136 and 0.7068, 0.6271 and 0.8901, and 0.2034 and 0.9738 respectively. Area under ROC curve for this test was 0.80.
A cut-off point of 10 mm is likely to be useful in supporting a diagnosis of tuberculosis in patients with strong clinical suspicion of tuberculosis, in other patients, 15 mm cut-off may be more suitable.
评估结核菌素皮肤试验不同临界值在诊断有呼吸道症状患者结核病中的效用。
对因各种呼吸道症状到胸科门诊就诊的连续新患者进行结核菌素皮肤试验。然后对所有受试者进行检查以确立诊断，并分为结核组和非结核组。绘制受试者工作特征（ROC）曲线以评估结核菌素皮肤试验的鉴别能力。还计算了不同临界值下的敏感性、特异性和预测值。
在250例患者中，根据临床和微生物学标准（不包括结核菌素试验），59例（23.6%）患有结核病。结核菌素试验在硬结直径大于5mm、10mm和15mm时的敏感性和特异性分别为0.8136和0.7068、0.6271和0.8901、0.2034和0.9738。该试验的ROC曲线下面积为080。
对于临床高度怀疑结核病的患者，10mm的临界值可能有助于支持结核病诊断；对于其他患者，15mm的临界值可能更合适。
