The system of blood collection in evacuated tubes for a number of laboratory tests is known to consist of numerous tubes, with the tops, which are color-coded and are responsible for indicating the tube contents. Most of the blood collection tubes are responsible for containing additives, which can accelerate the clotting of blood or can prevent blood from clotting.
Given below is a list of the blood collection tubes, which are commonly used.
The red tubes are not as common. They are used for a series of biochemistry tests that require serum, which is going to be affected adversely by separator gels, which are used in yellow bottles.
Additives- Red tubes contain silica particles, which are going to act as the clot activators. The clot activator is responsible for promoting blood clot with silica or glass particles.
Laboratory uses- These tubes are used for serum testing (glucose, triglycerides, cholesterol, HDL, potassium amylase, BUN, alkaline phosphatase, liver enzymes, or CK), antibody screening, blood bank serology, prototyping of red cell, DAT, monospot, RPR, ANA, and rheumatoid factor.
Additive- Anticoagulant SPS (Sodium Polyanethol Sulfonate) & ACD (acid citrate dextrose). The additive prevents the clotting of the blood and stabilizes the growth of bacteria.
Laboratory uses- These tubes are used for blood as well as bodily fluid cultures (Paternity, HLA, and DNA). Tubes that have ACD are used for cellular studies, paternity testing, and HLA typing.
Light blue tubes
The blue bottles are used for the hematology tests, which involve the system of clotting and require whole blood, which is inactivated, for the analysis.
Additive- Sodium citrate. It helps in binding and removing calcium in order to prevent the blood from clotting.
Laboratory uses- Coagulation, PT, FDP, APTT/PTT, TT, and factor assays.
The green tubes are the most common bottles, used primarily for the biochemistry tests, which are known to require whole blood or heparinized plasma.
Additive- Heparin (Sodium/lithium/ammonium). It inhibits the formation of thrombin in order to prevent blood clotting.
Laboratory uses- Chemistry testing, ammonia, insulin, chromosome screening, aldosterone, renin, and insulin.
These bottles are used for the hematology tests, where normally whole blood is needed for analysis.
Additive- EDTA. It helps in removing calcium, thereby preventing a blood clot.
Laboratory usage- Hematology testing, blood film for malaria parasites or abnormal cells, red cell folate, reticulocytes, parathyroid hormone, and monospot test.
These tubes are also very common and are used for the collection of blood.
Additive- Sodium fluoride and potassium oxalate. The sodium fluoride is responsible for acting as the antiglycolytic agent, which ensures that, there is no further breakdown of glucose after the sample has been collected. Potassium oxalate is responsible for removing calcium and it is also known to act as the anticoagulant.
Laboratory uses- Chemistry testing, mostly lactate and glucose and glucose tolerance test.
The different kinds of blood collection tubes have different functions and you should know all of them. This will help you to select the ideal tubes when you are collecting blood samples.