Thus 3 specimens are at most 30 ml or 30 / 5000 = 0.006 = 0.6% of your blood volume or more importantly the red blood cell volume.
For anyone not metrically inclined, that's just about one fluid ounce. If one ounce of blood makes a difference to a person, that person's health is in such a precarious condition that he should stay away from bikes altogether.