American Medical Technologist (AMT) Practice Exam 2025 – All-in-One Resource to Guarantee Exam Success!

In capillary blood collection, the first drop of blood is typically wiped away because it usually contains a higher concentration of tissue fluid. When a finger or heel is punctured to collect blood, the initial blood that emerges can mix with interstitial fluid and other contaminants from the skin surface. This tissue fluid can dilute the blood sample and potentially affect the accuracy of several laboratory tests. By discarding the first drop, the goal is to ensure that the subsequent sample is a more accurate representation of the blood composition, thus minimizing the interference caused by this extra fluid.

While other factors might be relevant in different contexts, such as contamination and clotting, the primary concern in this scenario is the presence of tissue fluid, which underscores the rationale for wiping away the initial drop. It helps ensure that the sample collected for testing is as pure as possible, ultimately leading to more reliable and accurate diagnostic results.