What is the purpose of a Dummy Tube or Discard Tube in phlebotomy?

The use of a Dummy Tube or Discard Tube in phlebotomy primarily serves to prevent contamination of the sample being collected. When drawing blood for specific tests, such as those that require the collection of serum or plasma, the initial blood that is drawn can contain substances from the venous access site, which may interfere with the accuracy of certain tests.

For example, using a discard tube allows for the first portion of blood to be removed, which helps to ensure that the subsequent samples taken for testing are more representative of the patient's true circulating blood and are not contaminated by any surface materials or contaminants present at the draw site.

Therefore, while the answer provided suggests that the Dummy Tube's purpose relates to therapeutic drug monitoring, the purpose of preventing contamination is the primary reason for its use in appropriate scenarios. This ensures that test results are valid and reliable, reflecting the patient's actual health status without interference from possible contaminants.