To which level should lavender and pink topped tubes be filled?

The correct filling level for lavender and pink topped tubes is at least 2/3 full. This is important because both types of tubes generally contain an anticoagulant that is critical for preventing blood from clotting during the testing process. Proper filling ensures an adequate blood-to-anticoagulant ratio, which is essential for accurate laboratory results. If the tube is not filled sufficiently, it may lead to an excess of anticoagulant relative to the blood volume, potentially causing false test results or interfering with the intended analysis. Filling the tube to at least 2/3 of its total volume helps to maintain the integrity of the sample and ensures accurate testing outcomes.

Other filling levels, such as completely or to a quarter or halfway, do not provide the same assurance that the optimal blood-to-anticoagulant ratio is achieved, which may compromise the testing process.