a b s t r a c t .

Much effort is currently being placed into developing new blood tests for cancer diagnosis in the hope of movingcancer diagnosis earlier and by less invasive means than current techniques,e.g.,biopsy.Currentmethodsareex-pected to diagnose and begin treatment of cancer within 62 days of patient presentation, though due to high vol-ume and pressures within the NHS in the UK any technique that can reduce time to diagnosis would allowreduction in the time to treat for patients. The use of vibrational spectroscopy, notably infrared (IR) spectroscopy,has beenunderinvestigation for many years with varying success. Thistechnique holds promise as iswouldcom-bine a generally well accepted test (a blood test) with analysis that is reagent free and cheap to run. It has beendemonstrated that, when asked simple clinical questions (i.e., cancervs.no cancer), results from spectroscopicstudies are promising. However, in order to become a clinically useful tool, it is important that the test differen-tiates a variety of cancer types from healthy patients. This study has analysed plasma samples with attenuatedtotal reflection Fourier-transform IR spectroscopy (ATR-FTIR), to establish if the technique is able to distinguishnormal from primary or metastatic brain tumours. We have shown that when asked specific questions,i.e.,high-grade gliomavs.low-grade glioma, the results show a significantly high accuracy (100%). Crucially, when com-bined with meningiomas and metastatic lesions, the accuracy remains high (88–۱۰۰%) with only minimal over-lap between the two metastatic adenocarcinoma groups. Therefore in a clinical setting, this novel techniquedemonstrates potential benefit when used in conjuction with existing diagnostic methods.