Rankin Stephen, McGuire Jacqueline, Chekroud Mohamed, Alakandy Likhith, Mukhopadhyay Babu
Internal Medicine, 3529NHS Greater Glasgow & Clyde, UK.
College of Medical, Veterinary and Life Sciences affiliated to the School of Medicine, 3526University of Glasgow, Glasgow, UK.
Scott Med J. 2022 May;67(2):71-77. doi: 10.1177/00369330211072264. Epub 2022 Feb 1.
Cerebrospinal fluid (CSF) analysis for xanthochromia is routinely used to exclude subarachnoid haemorrhage (SAH). In this study, we evaluated the sensitivity and specificity of xanthochromia (by NEQAS-spectrophotometry) in routine clinical practice in three acute hospitals, in patients with suspected SAH. We explored whether including CSF red cell count (RCC) with xanthochromia improved diagnostic accuracy.
In this retrospective analysis, all xanthochromia results were assessed over three consecutive years. Clinical information and Registry data were analysed to find all patients diagnosed with SAH. We correlated xanthochromia data with clinical and radiological findings.
There were 1761 xanthochromia performed. Of these, 26 (1.5%) were positive, 1624 (92%) negative and 72 (4.1%) were inconclusive. Of the 26 tests that were positive, 9 (35%) had confirmed SAH, 17 (65%) were falsely positive, with no false negative tests in our series. Xanthochromia identified 6% of all SAH diagnosed in the study. Incorporating RCC <1000 with xanthochromia, reducing false positive tests by 38% and inconclusive test by 85%.
The positive yield of xanthochromia is low but identified 6% of SAH. NEQAS-spectrophotometry is an excellent diagnostic method with 100% sensitivity, 99% specificity. Incorporating RCC markedly reduces false positive and inconclusive tests reducing need for further imaging.
脑脊液（CSF）黄变分析常用于排除蛛网膜下腔出血（SAH）。在本研究中，我们评估了在三家急症医院对疑似SAH患者进行常规临床实践时，采用国家外部质量评估服务（NEQAS）分光光度法检测黄变的敏感性和特异性。我们探讨了将脑脊液红细胞计数（RCC）与黄变检测相结合是否能提高诊断准确性。
在这项回顾性分析中，对连续三年的所有黄变检测结果进行了评估。分析临床信息和登记数据以找出所有被诊断为SAH的患者。我们将黄变检测数据与临床和影像学检查结果进行了关联。
共进行了1761次黄变检测。其中，26次（1.5%）为阳性，1624次（92%）为阴性，72次（4.1%）结果不确定。在26次阳性检测中，9次（35%）确诊为SAH，17次（65%）为假阳性，本研究系列中无假阴性检测。黄变检测在本研究中确诊的所有SAH病例中占6%。将RCC<1000纳入黄变检测，可使假阳性检测减少38%，不确定检测减少85%。
黄变检测的阳性率较低，但能识别出6%的SAH病例。NEQAS分光光度法是一种出色的诊断方法，敏感性为100%，特异性为99%。纳入RCC可显著减少假阳性和不确定检测，从而减少进一步影像学检查的需求。
