The invention describes a method of determining the presence of acute cerebral ischaemic disorder in a subject comprising: a. measuring the concentration of one or more purines in a body fluid of the subject, the purines being selected from adenosine, inosine, hypoxanthine, xanthine and ATP, and b. comparing the measured concentration with a threshold concentration of the one or more purines, wherein the threshold concentration is preferably in the range 5 μM to 15 μM and wherein a measured concentration higher than the threshold concentration indicates the presence of acute ischaemic disorder. Also is described a method of determining the absence of an acute cerebral disorder in a subject comprising: a. measuring the concentration of one or more purines in a body fluid of the subject, the purines being selected from adenosine, inosine, hypoxanthine, xanthine and ATP, and b. comparing the measured concentration with a threshold concentration of the one or more purines, wherein the threshold concentration is preferably below 4 μM and wherein a measured concentration lower than the threshold concentration indicates the absence of acute cerebral ischaemic disorder.