NHA Phlebotomy Certification Practice Exam

When a central venous access device (CVAD) is present, what should be done before specimen collection?

1. Blood is drawn and discarded before the specimen is collected

2. Specimens should always be collected from the line directly

3. Blood is collected without any additional steps

4. Adjustment of the catheter is required before collection

The correct answer is: Blood is drawn and discarded before the specimen is collected

When dealing with a central venous access device (CVAD), it is essential to draw and discard a sample of blood before collecting the specimen intended for testing. This practice ensures that any contaminants or residual blood from the tubing, which may not accurately reflect the patient's current state, are removed. Drawing a discard sample minimizes the risk of erroneous laboratory results caused by residual medications or fluids that might be present in the catheter or lines. Collecting specimens directly from the line without discarding a sample can lead to inaccurate test results, as the blood drawn could be influenced by these residual substances. The procedure of discarding an initial blood draw is a standard technique in phlebotomy to ensure the integrity and accuracy of the subsequent sample, which is critical for reliable diagnostics.