Fibromyalgia (FM) is a complex chronic pain condition. Its symptoms are nonspecific, and to date, no objective test exists to confirm FM diagnosis. Potential objective measures include the circulating levels of blood biomarkers. This systematic review and meta-analysis aim to review studies assessing blood biomarkers' levels in patients with FM compared with healthy controls. We systematically searched the PubMed, MEDLINE, EMBASE, and PsycINFO databases. Fifty-four studies reporting the levels of biomarkers in blood in patients with FM were included. Data were extracted, and the methodological quality was assessed independently by 2 authors. The methodological quality of 9 studies (17%) was low. The results of most studies were not directly comparable given differences in methods and investigated target immune mediators. Thus, data from 40 studies only were meta-analyzed using a random-effects model. The meta-analysis showed that patients with FM had significantly lower levels of interleukin-1 β and higher levels of IL-6, IL-8, tumor necrosis factor-alpha, interferon gamma, C-reactive protein, and brain-derived neurotrophic factor compared with healthy controls. Nevertheless, this systematic literature review and meta-analysis could not support the notion that these blood biomarkers are specific biomarkers of FM. Our literature review, however, revealed that these same individual biomarkers may have the potential role of identifying underlying pathologies or other conditions that often coexist with FM. Future research is needed to evaluate the potential clinical value for these biomarkers while controlling for the various confounding variables.

纤维肌痛 (FM) 是一种复杂的慢性疼痛病症。其症状是非特异性的，迄今为止，还没有客观的测试来确认 FM 的诊断。潜在的客观指标包括血液生物标志物的循环水平。本系统综述和荟萃分析旨在回顾评估 FM 患者与健康对照者血液生物标志物水平的研究。我们系统地检索了 PubMed、MEDLINE、EMBASE 和 PsycINFO 数据库。纳入了 54 项报告 FM 患者血液中生物标志物水平的研究。提取数据并由 2 位作者独立评估方法学质量。9 项研究（17%）的方法学质量较低。鉴于方法和研究的目标免疫介质的差异，大多数研究的结果不能直接比较。因此，仅使用随机效应模型对 40 项研究的数据进行了荟萃分析。荟萃分析显示，FM患者的白细胞介素1β水平显着降低，而IL-6、IL-8、肿瘤坏死因子-α、干扰素γ、C反应蛋白和脑源性神经营养因子水平升高与健康对照相比。然而，这种系统的文献综述和荟萃分析不能支持这些血液生物标志物是 FM 特异性生物标志物的观点。然而，我们的文献综述表明，这些相同的个体生物标志物可能具有识别潜在病理或经常与 FM 共存的其他病症的潜在作用。未来的研究需要评估这些生物标志物的潜在临床价值，同时控制各种混杂变量。