Final answer:
The first drop of blood is wiped away to avoid contamination from tissue fluids, debris, or antiseptics, ensuring the collected blood sample provides accurate diagnostic results.
Step-by-step explanation:
When using the microsampling technique to collect a blood sample, it is important to wipe away the first drop of blood with gauze because it may contain tissue fluids and cellular debris that could contaminate the blood sample. Contamination can affect the accuracy of diagnostic tests by altering the results of the blood analysis.
Moreover, the first drop may also have been exposed to any antiseptics used to clean the skin, which could kill certain microorganisms or interfere with tests. Clean blood is needed for a reliable capillary blood sample, which is often collected by capillary action in a small diameter glass tube.