SMARTChip: A Field Deployable Blood Test for Stroke, Capable of Detecting Brain Ischaemia From the Earliest Stages of Pathology

Stroke patients will be prospectively recruited to the trial on admission to A&E. The patient will undergo normal clinical assessment and treatment for stroke. As soon after admission as possible, a finger-prick blood sample will be taken from the patient and the SMARTChip device will be used to measure the levels of purines in the sample. A medical history of factors relevant to the purine test will also be established. This will include factors such as any medications that might alter purine levels, a prior history of strokes, diabetes, a history (individual or family) of gout, and when they last had food. The patient will also be given a CT head scan as part of their normal treatment.

In sub-set of patients repeated blood samples (once per hour for 6 hours) will be taken to gain information on how purine levels may change in blood following a stroke. In all patients, the blood purines will be re-tested at 24h (±3h).

All patients will be offered the option of an MRI brain scan at 24-72h post-admission and recruitment will continue until 100 patients with MRI measurements have been enrolled. The flexibility in the timing of the scan is to allow scheduling of the scan to fit in with other demands on the MRI. The purpose of the scan is to identify the nature of the cerebrovascular event and quantify any infarction or area of brain bleeding.

Control participants will give blood on 2 occasions 24h apart for a purine test. The purpose of this control is two-fold: 1) to establish the variability of blood purines in healthy controls and 2) to test whether stroke patients have elevated blood purine levels compared to healthy controls.

Healthy volunteer feeding controls will give a baseline blood sample, eat a simple purine rich meal (a meat sandwich) and then give 4 more blood samples at 10, 30, 60 and 120 minutes following the meal. The purpose of this control is to test whether ingestion of a recent meal might alter baseline blood purine measurements.