The phlebotomy order of draw can be confusing. We’ve outlined the six steps you should take so you will never have to wonder again.
The process of drawing blood may seem easy for a non-professionals or those who have very little knowledge on phlebotomy. However, there are several specific guidelines to follow in order to ensure the integrity of test results.
Below are the 6 steps to the phlebotomy order of draw. This drawing process is critical to master and is strictly followed at all different medical institutions.
The Six Steps to Phlebotomy Order of Draw
A quick reference for the phlebotomy order of draw
1. Sterile Blood Culture Tubes or Vials
Sterile specimens are drawn first to prevent contamination that can occur during the procedure. The specimens you should draw first are blood culture bottles and SPS (yellow top) tubes. Sterile technique is critical to obtaining a perfect specimen.
2. Blue Top Tubes
Blue top tubes are used for coagulation studies and contain citrate additives. They have a light blue shield/stopper as well as a clear shield used over the blue stopper.
3. Red Top Tubes
These tubes may come with or without clot activator or gel separator. They may look like a red and black tiger top stopper, gold shield, or a red shield/stopper. These are used to draw samples for blood bank and HCG levels (pregnancy hormones).
4. Green Top Tubes
These tubes contain heparin as an additive and may come with or without a gel plasma separator. They may have a green and gray stopper, light green shield, as well as the green shield/stopper. These tubes are used to test ammonia and blood chemistry levels.
5. Purple Top Tubes
EDTA (Ethylenediaminetetraacetic Acid) tubes use a lavender stopper/shield, white (pearl) shield, pink stopper/shield, royal blue shield or tan shield. These tubes can be used to test CBC (Complete Blood Count), Hematocrit, Hemoglobin, and ESR (Erythrocyte Sedimentation Rate).
6. Gray Top Tubes
These glycolytic inhibitor tubes have a gray stopper/shield and are used for a variety of glucose studies.
According to the Clinical Laboratory Standards Institute (CLSI), the specific order in which the tubes are filled should be the same, regardless of whether a Vacutainer sleeve method or a syringe draw and transfer method is used. The phlebotomy order of draw should also remain the same despite whether the tubes are glass or plastic.
The order of draw is followed in every venous blood collection. This system is also used for inpatients, outpatients, and home care. It is safe for use on all ages. It is very important to follow this order of draw in order to avoid any lab errors as a result of cross-contamination from additives. Even a slightest contamination of a certain additive from one tube to another may alter the overall results, and this could harm the life of a patient.
You may want to have a cheat sheet with you while you work or invest some time organizing your tubes in the order of draw before you go to perform a venipuncture. The phlebotomy order of draw may be challenging when you first start working, but with practice and diligence, you will succeed.