Evaluation of between-assay consistency among laboratory testing methods for neurosyphilis: a systematic review

We conducted a systematic review to analyse the consistency of nontreponemal-specific tests of Treponema pallidum in cerebrospinal fluid. We searched the PubMed, EMBASE, Web of Science, CNKI, Wanfang and Chongqing VIP databases. The inclusion criteria were studies conducted on nontreponemal-specific tests in cerebrospinal fluid (CSF) within the same population. Exclusion criteria were studies with incomplete data or where we were unable to obtain the full text, duplicate reports, case reports and studies without sensitivity or specificity results. We used kappa value analysis and McNemar's test to analyse study consistency. We initially collected a total of 198 articles and ultimately included six articles that involved 429 patients with neurosyphilis. The performance between venereal disease research laboratory tests (VDRL) and the reactive plasma regain or toluidine red serum unheated test was similar. The kappa value for consistency between VDRL and reactive plasma regain was >0.8 in three articles, and was 0.892 for consistency between VDRL and toluidine red serum unheated test in one article. Our results suggested that CSF-reactive plasma regain or CSF-toluidine red serum unheated test may serve as alternative tests in the diagnosis of neurosyphilis with CSF-VDRL.