Final answer:
The tan color tube top in blood collection usually contains the additive EDTA, used as an anticoagulant for preserving blood samples for testing.
Step-by-step explanation:
The color coding system for blood collection tubes is standardized and is used to identify the additive inside the tube, which prevents the blood from clotting or preserves certain components of the blood. The tan color tube top is associated with blood lead testing and typically contains the additive EDTA (ethylenediaminetetraacetic acid), which acts as an anticoagulant by binding to calcium in the blood.