Avoiding Carryover in Blood Draws
February 19, 2012
The significance of maintaining the proper order of blood draws continues to be misunderstood by some phlebotomy technicians. Even though it has been more than thirty years since the required order of blood collection tubes was announced, misdiagnosis still occurs in laboratories throughout the country.
A change in order did take place with the advent of glass tubes being replaced by plastic tubes and because glass acted as a natural clot activator, no additive was necessary to aid in clotting. This revision in the proper order of draws was necessary to avoid contamination of the additives in the new plastic tubes.
Contamination occurs when the blood or additive makes contact with the needle that is filling the tube and then transfers even a minute amount of additive or blood to the next tube being filled. There are several factors that can cause this transfer or carryover in both vacuum and syringe draws. In tube holder draws, carryover will occur directly from the needle that is in the holder as tubes are being exchanged. In the case of syringe draws, the contamination happens through the needle of the safety transfer device.
Another factor that can cause carryover is when there is improper orientation of the tube while using a tube holder. If exact positioning were possible in all draws allowing the tubes to be filled from bottom to top every time, the specific order of draws would not be such a critical issue. In the course of your phlebotomy training, it should have been strongly emphasized that this is virtually impossible given that each patient is different and an endless variety of patient arm positions occur in the course of any draw.
When situations of carryover exist, test results can be significantly affected and can result in devastating and life-threatening medical errors. Technicians who take their careers seriously and have attained their phlebotomy certification understand the importance of always following accepted standard procedures in every blood draw. It is also recommended that all those involved in the field regularly update their skills either through accredited phlebotomy programs or if time is a factor, there are several online phlebotomy certification classes available for retraining. The safety of all patients depends on each phlebotomy technician understanding the importance of following proper procedures with every blood draw.
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Phlebotomy Schools
February 22, 2012