Chan Toby Chun Hei, Chen Sammy Pak Lam, Mak Chloe Miu, Ching Chor Kwan, Luk Kristine Shik, Tsang Yat Ming, Leung Daniel Cheuk Wa
Chemical Pathology Laboratory, Department of Pathology, Hong Kong Children's Hospital, Kowloon, Hong Kong.
Chemical Pathology Laboratory, Department of Pathology, Princess Margaret Hospital, Kowloon, Hong Kong.
J Clin Pathol. 2020 Dec;73(12):800-802. doi: 10.1136/jclinpath-2019-206397. Epub 2020 May 18.
Tuberculous meningitis (TBM) is a severe infection which may lead to serious complication and mortality. Prompt diagnosis and treatment are essential. There is a need for a simple and fast laboratory test to differentiate TBM from other causes.
Retrospective review was conducted for cerebrospinal fluid adenosine deaminase (CSF-ADA) activity which was measured at the Chemical Pathology Laboratory of Princess Margaret Hospital, the sole centre providing such service in Hong Kong, for 51 patients with suspected meningitis from nine local hospitals between June 2014 and July 2017. TBM diagnosis was defined by positive culture and/or nucleic acid amplification test result of complex in CSF.
CSF-ADA activity was significantly higher in the TBM group (8.6±2.1 IU/L, n=8) than that of the non-TBM group (2.8±5.9 IU/L, n=43). The optimal clinical cut-off of 5.1 U/L for TBM diagnosis in our laboratory yielded 100% sensitivity, 91% specificity, positive likelihood ratio of 10.8 and negative likelihood ratio of 0. In rare circumstance, false elevation may be seen in non-tuberculous cause, such as central nervous system lymphoma and fungal infection.
We recommend the use of CSF-ADA activity, which is a simple, fast and robust test for early differentiation of TBM from other causes, to facilitate timely initiation of antituberculous treatment and potentially improve patients' outcome.
结核性脑膜炎（TBM）是一种严重感染，可导致严重并发症和死亡。及时诊断和治疗至关重要。需要一种简单快速的实验室检测方法来鉴别TBM与其他病因。
对2014年6月至2017年7月期间来自香港9家当地医院的51例疑似脑膜炎患者的脑脊液腺苷脱氨酶（CSF-ADA）活性进行回顾性研究，CSF-ADA活性检测在玛嘉烈医院化学病理实验室进行，该实验室是香港唯一提供此项检测服务的中心。TBM诊断依据脑脊液中培养阳性和/或核酸扩增检测结果呈阳性确定。
TBM组（8.6±2.1 IU/L，n = 8）的CSF-ADA活性显著高于非TBM组（2.8±5.9 IU/L，n = 43）。本实验室TBM诊断的最佳临床截断值为5.1 U/L，敏感性为100%，特异性为91%，阳性似然比为10.8，阴性似然比为0。在罕见情况下，非结核病因如中枢神经系统淋巴瘤和真菌感染可能出现假升高。
我们建议使用CSF-ADA活性检测，这是一种简单、快速且可靠的检测方法，可早期鉴别TBM与其他病因，有助于及时开始抗结核治疗并可能改善患者预后。
