NHA Phlebotomy Certification Practice Exam

Forcing blood from a syringe into an evacuated tube:

1. Prevents the blood from clotting.

2. Can only be done when using a small syringe.

3. May hemolyze the specimen.

4. Is required when using a transfer device.

The correct answer is: May hemolyze the specimen.

Forcing blood from a syringe into an evacuated tube may hemolyze the specimen because this action exerts excessive pressure on the red blood cells. Hemolysis is the breakdown of red blood cells, which can occur when blood is pushed too forcefully through the narrow opening of a syringe or transfer device into a collection tube. This mechanical trauma can disrupt the cell membrane, leading to the release of hemoglobin into the plasma and potentially affecting test results. Understanding this principle is crucial, as hemolyzed samples may yield inaccurate laboratory results, impacting patient care. Proper techniques during blood collection help ensure that specimens remain intact and reliable for diagnostic purposes.