"While there are different reasons that blood flow may be impeded, there are also ways to try to correct the issue. The simplest effort would be to change the position of the needle, either by moving it forward slightly or pulling it back slightly, if it is suspected to have penetrated too far. There are also times that a vacutainer may not be sealed correctly, which may prevent blood from being pulled into the tube. Trying a new tube may resolve this issue. Also, if a tourniquet is too tight, it may suppress blood flow. We always want to try to resolve the issue without having to do a second puncture, but sometimes that is the only option left."

There are various reasons that a venipuncture may appear to be unsuccessful, and often, there are simple ways to 'fix the problem.' The interviewer wants to know that you can make a judgment call on how to proceed when a venipuncture doesn't seem to be producing blood flow. Share your knowledge.

"There could be a couple of different reasons that blood doesn't flow properly into a collection tube. One of the most common is that the bevel of the needle is against a vein wall. Simply repositioning the needle could resolve this issue and allow blood to flow freely."