If you carefully follow the instructions provided, you should be able to collect sufficient blood.
It is particularly important to ensure that you are well hydrated and that your hand is warm before you start trying to collect your sample. Please make sure to read the instructions carefully and watch the video linked below so that you are confident with the process that you need to follow.
However, should you not be able to produce enough blood to reach the indicated line on the tube, we recommend that you send the sample in anyway, as sometimes we are able to produce results with a smaller volume.
https://www.exeterlaboratory.com/instructions/