What is the recommended action if blood does not flow into the collection tube during venipuncture?

When blood does not flow into the collection tube during venipuncture, changing the angle of the needle can be a beneficial action. This adjustment may help in several ways. First, a needle that is not perfectly positioned can inadvertently obstruct blood flow; even a slight change in angle can help the needle to better access the vein. Secondly, if the needle has moved out of the vein slightly or if it has penetrated the vein wall, adjusting the angle may allow for re-entry into the vein without needing to withdraw the needle entirely.

While the other options could be considered, they may not be the most effective immediate response. Trying a different blood collection tube might not address the underlying issue of the needle's position if that’s the cause. Removing the needle and starting over could introduce unnecessary pain for the patient and could lead to decreased success at the same site. Waiting might be ineffective if the issue is due to the needle's position rather than any other reason, such as the patient's circulatory status. Therefore, changing the angle of the needle is often a quick and effective method to resolve the issue with blood flow during venipuncture.