Asawavichienjinda T, Sitthi-Amorn C, Tanyanont V
Department of Medicine, Maharaj Nakhon Ratchasima Hospital, Nakhon Ratchasima, Thailand.
J Med Assoc Thai. 1999 Jan;82(1):65-71.
The incidences of HIV-AIDS patients with opportunistic infections of the central nervous system are increasing. Of these, cryptococcal meningitis is the most important and serious. A simple method for the diagnosis of cryptococcal meningitis is needed despite its variable clinical features and the lack of a capacity in most health facilities in Thailand to exclude it from other diseases especially mass lesions in the brain.
To identify the capability and cut off point of serum cryptococcal antigen for diagnosis and screening of cryptococcal meningitis in HIV-AIDS patients.
One hundred consecutive cases of HIV-AIDS patients suspected of having central nervous system infections were prospectively recruited for the study. The serum of all patients were examined for cryptococcal antigen by latex agglutination test, the Pastorex Cryptococcus manufactured by Sanofi Diagnostic Pasteur, France. If a test was positive, the serum dilution was carried out using 10-fold serial dilution. Every patient went through pre-defined standard investigations to derive at a definite diagnosis. The gold standard for diagnosis of cryptococcal meningitis was the presence of encapsulated yeast forms in the cerebrospinal fluid or a positive culture for cryptococcal neoformans from the cerebrospinal fluid.
Of 100 patients enrolled in this study, 58 patients had cryptococcal meningitis and serum cryptococcal antigen was detectable in 60 patients. If the cut-off point for a positive test was when the serum cryptococcal antigen titer was more than zero, then, the sensitivity of the test was 91.4 per cent, the specificity was 83.3 per cent, likelihood ratio if test positive (LR+) was 5.47, likelihood ratio if test negative (LR-) was 0.1, false positive was 16.7 per cent, false negative was 8.6 per cent.
We conclude that serum cryptococcal antigen is a simple and rapid screening method for diagnosis of cryptococcal meningitis.
感染中枢神经系统的艾滋病患者的发病率正在上升。其中，隐球菌性脑膜炎最为重要且严重。尽管隐球菌性脑膜炎临床特征多样，而且泰国大多数医疗机构缺乏将其与其他疾病（尤其是脑部占位性病变）相鉴别的能力，但仍需要一种简单的诊断方法。
确定血清隐球菌抗原在诊断和筛查艾滋病患者隐球菌性脑膜炎方面的能力及临界值。
前瞻性招募了100例疑似中枢神经系统感染的艾滋病患者进行研究。使用法国赛诺菲诊断巴斯德公司生产的帕斯托隐球菌乳胶凝集试验检测所有患者血清中的隐球菌抗原。如果检测呈阳性，则采用10倍系列稀释法进行血清稀释。每位患者都接受了预先定义的标准检查以得出明确诊断。隐球菌性脑膜炎诊断的金标准是脑脊液中存在有荚膜酵母形式或脑脊液新型隐球菌培养阳性。
本研究纳入的100例患者中，58例患有隐球菌性脑膜炎，60例患者血清中可检测到隐球菌抗原。如果阳性检测的临界值是血清隐球菌抗原滴度大于零，那么该检测的灵敏度为91.4%，特异性为83.3%，检测阳性的似然比（LR+）为5.47，检测阴性的似然比（LR-）为0.1，假阳性为16.7%，假阴性为8.6%。
我们得出结论，血清隐球菌抗原是诊断隐球菌性脑膜炎的一种简单快速的筛查方法。
