On occasion, blood may stop flowing from the punctured site before the required amount of blood is obtained. When this happens, it is not recommended to squeeze harder. This only serves to cut off the supply of blood to the capillary bed. Additionally, squeezing with too much force, especially on the heel of an infant, may cause injury to the patient and may contaminate the specimen with tissue fluid. To achieve good blood flow, alternately applying gentle pressure to the area and releasing it is recommended.
The phlebotomist should never scrape the skin with the collection device in an attempt to scoop up the blood that is lying on the surface of the finger or heel. This could cause the blood specimen to hemolyze, making the specimen unacceptable for some laboratory tests. Always allow the drop to flow freely into the collection tube.
If a clot has formed, an attempt could be made to dislodge it and re-establish blood flow by wiping the puncture site again with sterile gauze, massaging the finger or heel gently, and attempting to recollect the specimen.
If blood is not flowing freely from the initial puncture, it may be necessary to perform a second puncture to obtain enough blood for the testing required. If a second puncture must be performed, do not re-puncture the same site. When a second puncture is made, the blood should not be added to the previously collected tube. A new site, device, and alcohol pad must be used.
