Most of the people reading this might know that the blood is collected from a patient and they are put inside a tube in a specific order, that’s the order of draw.
Phlebotomy order of draw is necessary so that the additives the tubes contains doesn’t get cross-contaminated.
The bad thing is that the order is tough to remember, and many phlebotomists can’t remember it very all; it is tough for people in training to remember as well as some professionals too can’t remember the pattern.
Phlebotomy is not just drawing blood from a patient. It is a subject which covers every aspect of handling the specimen properly so that they can be used for proper analysis which can make a proper diagnosis and treatment plan for the patient. So, for proper handling and care of the specimens, they should be stored in such a way that they do not get contaminated and compromised. There are also special considerations taken at the time of blood cultures and indwelling catheter line draw. So, the order of draw plays a vital role in all of them.
Why drawn blood have chances of contamination?
Different additives are added indifferently top colored tubes to preserve the blood sample. If the specific order of tubes is not followed, then the specimen gets cross-contaminated, and this will challenge the accuracy of the test result. Blood tests are very important for the diagnosis of the patient’s disease, and a slight error can result in mistreatment. So, phlebotomists are trusted by medical authorities to draw the blood properly and expected that the use the use of the phlebotomy tubes and the correct method of drawing blood.
How is the order of draw determined?
Clinical Laboratory Standards Institute (CLSI) approves the order of draw and publishes it. The healthcare and various testing centers should follow the most recent pattern for the accuracy of the tests.
The order recommended
In November 2007, the latest update took place, known as H3-A6. The order is the same for plastic and glass blood collection tubes, evacuated system and syringe. Previously, the process of collection of blood used to use separate order, but now it is obsolete as researchers found that there’s no need to use a different order.
So, let’s look into different acronyms to make the whole thing simpler and easier to understand:
SST: Serum Separator Tube
FDP: Fibrin degradation products
SPS: Sodium polyanethole sulfonate
EDTA\; ethylenediaminetetraacetic acid
CLSI’s recommendation on the order of draw:
SPS (Blood Culture – Yellow: In microbiology blood culture is used. The additive of the broth mixture is used to preserve the sample.
Sodium Citrate – Light Blue: Used for coagulation test and uses sodium citrate as an additive.
No Additive – Plain Red: Used for regular venipuncture.
Clot Activator – Plastic Red: Plastic red stoppers are used in these bottles, and this bottle is used to clot blood and with the help of centrifugation serums are separated.
SST/Clot Activator/Gel w – Gold, Gray/Red: No additive is used in serum separator tube. Centrifugation will separate serums with the help of activator for a clot.
Lithium Heparin or Sodium – Green: Additives lithium heparin is used as an anticoagulant.
EDTA – Tall Pink, Lavender, Purple: EDTA anticoagulants are used from calcium salts to remove calcium.
Potassium Oxalate, Sodium Fluoride – Gray: Potassium oxalate or sodium fluoride is used as an antiglycolytic agent to preserve glucose for five days.
FDP – Royal Blue: This is used to test for DVT, a blood clot in a deep vein, stroke, embolism and other major clotting disorders.