Blood tests can provide useful information about brain health, but taking blood from a vein is not always practical, especially in remote or outdoor settings. This study tested Tasso+, a small device worn on the upper arm that collects a tiny blood sample with minimal discomfort. Samples were taken before exercise, immediately afterwards and around one to one-and-a-half days later. The researchers also tested whether samples remained reliable when they were kept at room temperature for up to 72 hours before processing. Results from Tasso+ were compared with standard blood samples taken from a vein and with another small-sample collection method. Tasso+ successfully measured several important signs of brain health and the body’s response, even when processing was delayed. This suggests that the device could make brain-health research easier in places where standard blood collection is difficult, and may allow people to collect samples themselves at home.