Which of the following actions should a phlebotomist take when interacting with a patient who has a "Contact Precautions" sign on their door?

Choice A reason:
While ensuring that employees receive training regarding workplace hazards is important, it is not the general concept behind standard precautions. Training is a part of the broader safety measures but does not encompass the core idea of standard precautions, which is to prevent infection transmission.

Choice B reason:
Providing information about hazardous chemicals within the environment is related to the Right-to-Know standard, which is part of the Hazard Communication Standard. This is not the main concept of standard precautions, which focus on preventing the spread of infections, particularly in healthcare settings.

Choice C reason:
Assuming that all body fluids are potentially infected with bloodborne pathogens is the essence of standard precautions. This approach dictates that healthcare workers should treat all body fluids as if they are infectious and therefore use appropriate protective measures to prevent exposure and transmission of diseases.

Choice D reason:
Maintaining a workplace free of environmental hazards is a broad occupational safety goal but does not specifically describe the general concept behind standard precautions. Standard precautions are more focused on infection control practices rather than the broader scope of all environmental hazards.

Choice A reason:
The high pressure in the arterial system is not a factor in the filling of blood collection tubes during venipuncture. Arterial blood is not typically collected using evacuated tubes; these are used for venous blood collection, where the pressure is lower.

Choice B reason:
While the venous system does have pressure that aids in blood flow, it is not the high pressure that causes blood collection tubes to fill. Venous pressure is relatively low compared to arterial pressure, and on its own, it is not sufficient to fill the vacuum tubes used in venipuncture.

Choice C reason:
The positive pressure created by the tourniquet can help engorge the veins, making them easier to access, but it does not directly cause the blood collection tubes to fill. The tourniquet's role is to assist in vein visualization and palpation rather than in the filling of the tube.

Choice D reason:
The negative pressure within the tube is the correct factor that causes blood collection tubes to fill during venipuncture. When the needle punctures the patient's vein and then the tube stopper, the vacuum in the tube pulls blood into it until the vacuum is exhausted or the tube is filled. This is why it is essential not to allow the tube contents to contact the stopper, as backflow into the venous system can cause adverse reactions.