Gulf War illness (GWI) is a chronic illness with no known validated biomarkers that affects the lives of hundreds of thousands of people. As a result, there is an urgent need for the development of an untargeted and unbiased method to distinguish GWI patients from non-GWI patients. We report on the application of laser-induced breakdown spectroscopy (LIBS) to distinguish blood plasma samples from a group of subjects with GWI and from subjects with chronic low back pain as controls. We initially obtained LIBS data from blood plasma samples of four GWI patients and four non-GWI patients. We used an analytical method based on taking the difference between a mean LIBS spectrum obtained with those of GWI patients from the mean LIBS spectrum of those of the control group, to generate a “difference” spectrum for our classification model. This model was cross-validated using different numbers of differential LIBS emission peaks. A subset of 17 of the 82 atomic and ionic transitions that provided 70% of correct diagnosis was selected test in a blinded fashion using 10 additional samples and was found to yield 90% classification accuracy, 100% sensitivity, and 83.3% specificity. Of the 17 atomic and ionic transitions, eight could be assigned unambiguously to species of Na, K, and Fe.

海湾战争疾病 (GWI) 是一种慢性疾病，没有已知的经过验证的生物标志物会影响数十万人的生活。因此，迫切需要开发一种非靶向和无偏见的方法来区分 GWI 患者和非 GWI 患者。我们报告了应用激光诱导击穿光谱 (LIBS) 来区分 GWI 受试者和作为对照的慢性腰痛受试者的血浆样本。我们最初从四名 GWI 患者和四名非 GWI 患者的血浆样本中获得 LIBS 数据。我们使用了一种分析方法，该方法基于从对照组的平均 LIBS 光谱中获取 GWI 患者的平均 LIBS 光谱之间的差异，为我们的分类模型生成“差异”光谱。使用不同数量的差分 LIBS 发射峰交叉验证了该模型。在提供 70% 正确诊断的 82 个原子和离子跃迁中选择了 17 个子集，使用 10 个额外样本以盲法方式进行测试，发现其分类准确度为 90%，灵敏度为 100%，特异性为 83.3%。在 17 个原子和离子跃迁中，有 8 个可以明确地分配给 Na、K 和 Fe 物种。