Abstract
Blood tests are widely carried out to screen for various diseases. However, this kind of test causes physical and mental stress for the subjects. The authors aim to develop a semi-invasive blood-collecting needle that needs no power source for the pump mechanism. In this study we fabricated a capillary action needle that can automatically collect a blood sample. This needle has a half-open crevice in the tip. For the physical characteristics of the blood-collecting needle to be evaluated, the relationship between the size and the suction time and/or suction volume were measured by use of an isotonic sodium chloride solution, whole rabbit blood, and whole human blood. Next, to evaluate the degree of invasion, the diameters of erythema in the auricles of rabbits were measured. As a result, the selection of the correct size of blood-collecting needle enabled the collection of 0.1μL of whole human blood in 10 seconds. Moreover, by a comparison of the observed diameters of the erythemas, it was shown that the invasiveness of the blood-collecting needle was smaller than with commercial needles. It thus became clear that this fulfills the fundamental functions of a semi-invasive blood-collecting needle.
