Not all goals for blood analysis are the same – requiring the use of unique and effective protocols. Collection bottles for blood analysis come in various colors (colours EU), indicating the contents of the tube. This coding system makes it easier for laboratories to stay organized when handling a number of a series of different biological tests.
Each vial contains an additive that accelerates clotting or prevents clotting. Depending on your laboratory’s goals for analysis, each color-coded bottle will facilitate different reactions to help better assess a sample for research or medical purposes.
Here is a list of the eight most common color-coded blood collection vials:
Red
This less common collection tube bottle is used in biochemistry testing that requires a specialized serum. It is possible for this serum to be adversely affected by separating gels used in other common blood collection bottles. The goal of using this additive is to promote blood clotting via silica particles with clot activating properties
Some applications for red collection bottles include testing for glucose, cholesterol, liver enzymes, and alkaline phosphatase. They are commonly used for antibody screening, red cell phototyping, DAT, RPR, monospot, and rheumatoid factor testing.
Yellow
Formulated with the additive anticoagulant sodium polyanetholesulfonate (SPS) and acid citrate dextrose (ACD), yellow collection bottles are designed to prevent blood from clotting while stabilizing bacterial growth in a sample. This is useful when analyzing blood or bodily fluid samples for screenings such as HLA, DNA, and paternity tests.
The SPS aids in the recovery of microorganisms by slowing down/stopping the actions of complement, phagocytes, and some antibiotics. ACD is useful for cellular studies and identification of genetic material.
Green
Green collection tubes bottles are used in biochemistry applications that require heparinized plasma or whole blood for analysis. This is made possible with the use of heparin additives such as sodium, lithium, or ammonium.
The additive acts as an inhibitor for thrombin formation, preventing clotting for use in further analysis. Some methods include plasma determinations, chromosome screening, and insulin testing.
Light blue
Light blue collection tubes bottles are used for hematology tests involving the clotting system, requiring samples that are inactivated whole blood for proper analysis.
This is performed with the additive sodium citrate, which binds and removes calcium to prevent the blood from clotting.
There are several applications that require studying the coagulation (clotting process):
- Prothrombin time (PT)
- Activated partial thromboplastin time (APTT/PTT)
- Fibrinogen degradation products (FDP)
- Thrombin time (TT)
- Factor assay
Purple
Purple collection tubes bottles also require whole blood samples for analysis. The sample is treated with ethylenediaminetetraacetic acid (EDTA), which removes calcium preventing clotting of the blood sample.
This test vial is known for its use analyzing blood film for abnormal cells such as malaria parasites, red cell folate, and reticulocytes.
Grey
Grey tubes bottles are formulated with potassium oxalate and sodium fluoride and are primarily used for chemistry testing such as glucose and lactate testing (specifically glucose tolerance test).
Sodium fluoride acts as an antiglycolytic agent, ensuring that no further glucose breaks down in the sample. Potassium oxalate then removes calcium, operating as an anticoagulant to stabilize the sample.
Royal blue
These collection tubes vials are used for the testing of trace elements in a blood sample, such as zinc, copper, lead, and mercury. Royal blue collection bottles are a fundamental tool for nutritional chemistry testing.
They are developed with two additives; sodium heparin and sodium EDTA, to inhibit the formation of thrombin in the collected sample
Black
Black collection tubes bottles are designed for pediatric ESR testing. Sodium citrate interacts with the sample to form calcium salts which remove calcium from the sample material.
This test application is an important tool for diagnostic care for children that may have irregular inflammation in the body, leading to the diagnosis of other critical conditions.