Various blood collection tubes, additives content and Laboratory Uses

Blood collections is one of the basic step taking as a medical personnel particularly with at the level of the  Laboratory department but blood collection tubes is another confusing part of this whole process.Many students  are unable to specify which tube with its corresponding anticoagulant are used for various laboratory tests.So these article will help identifying the various test tubes and their corresponding anticoagulant including the test used for.

The evacuated tube system for blood collection in use for various laboratory tests consists of tubes of various sizes, with particular colored caps indicating tube contents. Most blood collection tubes contain  additive that either accelerates clotting of  blood (clot activator) or prevents the blood from clotting that's is anticoagulants.

Knowing these various test tubes and their corresponding anticoagulant or clot activator is very beneficial and ease blood collections and blood sample processing minimizing random errors.

So below are the most commonly used blood collection tubes including their respective additives and uses in blood collection and processing:

Various blood collection tubes and their respective anticoagulants 1. BLACK ESR Test tube and anticoagulant Additive: Sodium Citrate ·         Function: Forms calcium salts thats is binds calcium in the blood. Calcium is required for blood clotting. Since it is bound up the blood cannot clot resulting in a whole blood sample ·         Laboratory uses: Erythrocyte sedimentary Rate (ESR) 2. LAVENDER OR PURPLE These tubes  are generally used for haematology tests inorder to update whole blood for analysis      Additive: EDTA (Ethylenediaminetetraacetic Acid)      Function: strongly and irreversibly chelates (binds) calcium ions, preventing blood from clotting.  Laboratory uses: Used for (ESR, CBC w/diff., HgBA1c)     blood film for abnormal cells or malaria parasites, reticulocytes, red cell folate, Monospot test for EBV, parathyroid hormone (PTH) 3. RED

Plain tubes with no additive

They are used for  biochemistry tests to obtain serum

·         Additive: None or contains silica particles which act as clot activators.

·         Function: Clot activator promotes blood clotting with glass or silica particles.

·         Laboratory Uses: Serum testing mostly Biochemistry (glucose, cholesterol, triglycerides, HDL, potassium, amylase, alkaline phosphatase, BUN, CK, liver enzymes), blood bank, serology (RH Typing, Antibody screening, Red Cell Phototyping, DAT, RPR, monospot, rheumatoid factor, ANA)

4. GREEN

Heparin test tube

·         This less commonly used bottle is for biochemistry tests which require heparinised plasma or whole blood for analysis.

·         Additive: Heparin (Sodium/Lithium/Ammonium)

·         Function: Inhibits thrombin formation to prevent clotting

·         Laboratory uses: Chemistry Testing (Plasma determinations in chemistry) : ammonia, carboxyhemoglobin & STAT electrolytes, chromosome screening, insulin, renin and aldosterone

5. GREY

Sodium fluoride test tube

·         Additive: Potassium oxalate and Sodium fluoride

·         Function: Sodium fluoride acts as an antiglycolytic agent to ensure that no further glucose breakdown occurs within the sample after it is taken. Potassium oxalate removes calcium and acts as an anticoagulant.

·         Laboratory uses: Chemistry testing, especially glucose(sugar) and lactate, Glucose tolerance test (GTT)

6. YELLOW

·         Additive: anticoagulant SPS (Sodium Polyanetholsulfonate) & ACD (acid citrate dextrose)

·         Functions: Prevents the blood from clotting and stabilizes bacterial growth.

·         Laboratory Uses: Blood and bodily fluid cultures (HLA, DNA, Paternity)
Tubes with SPS – For Blood and bodily fluid cultures (HLA, DNA, Paternity). The SPS aids in the recovery of microorganisms by slowing down/ stopping the actions of complement, phagocytes, and certain antibiotics.
Tubes with ACD are for cellular studies, HLA typing, paternity testing.

7. ROYAL BLUE

·         Additive: Sodium Heparin also Sodium EDTA

·         Function: Inhibits Thrombin formation to prevent

·         Laboratory uses: Chemistry trace elements (such as Zinc, Copper, Lead and Mercury), toxicology, and nutritional chemistry testing

8. LIGHT BLUE                                               

Sodium Citrate test tube

the blue bottle is used for hematology tests involving the clotting system, which require inactivated whole blood for analysis.

·         Additive: Sodium Citrate

·         Function: Binds and remove calcium to prevent blood from clotting

·         Laboratory uses: Coagulation (clotting process-P.T)
PT (Prothrombin Time – evaluates the extrinsic system of the coagulation cascade & monitors coumadin therapy)
APTT/ PTT (Activated Partial Thromboplastin Time – evaluates the intrinsic system of the coagulation cascade & monitors heparin therapy)
FDP (Fibrinogen Degradation Products)
TT (Thrombin Time)
Factor assays