Principle and classification of vacuum blood collection

Update:22-05-2020
Summary:

The principle of vacuum blood collection is to pump the […]

The principle of vacuum blood collection is to pump the blood collection tube with the head into different vacuum degrees in advance, and use its negative pressure to automatically collect venous blood samples. One end of the blood collection needle is inserted into the human vein, and the other end is inserted into the rubber plug of the vacuum blood collection tube. Under the action of negative pressure, the human venous blood is drawn into the blood sample container through the blood sampling needle. Under a single venipuncture, multiple tubes can be collected without leakage. The volume of the internal cavity connecting the blood sampling needle is very small, so the influence on the volume of blood sampling can be ignored, but the probability of counterflow is relatively small. If the volume of the internal cavity is larger, it will consume a part of the vacuum degree of the blood sampling vessel, so as to reduce the volume of blood collection.

There are 9 kinds of vacuum blood vessels, which can be distinguished according to the color of the cover

1. Red cap of common serum tube
There are no additives, anticoagulant and procoagulant components in the blood vessels, only vacuum. It is used for routine serum biochemistry, blood bank and serology related tests, various biochemical and immunological tests, such as syphilis, hepatitis B quantification, etc. it does not need shaking after blood sampling. The sample was made of serum, which was put into a 37 ℃ water bath for more than 30 minutes after blood sampling, centrifuged, and the upper serum was reserved.
2. Fast serum tube orange head
There are coagulants in the blood vessels to accelerate the coagulation process. The rapid serum tube can coagulate the collected blood within 5 minutes, which is suitable for the series of emergency serum tests. It is the most commonly used coagulation promoting tube for daily biochemistry, immunity, serum, hormone, etc. it can be reversed and mixed 5-8 times after blood sampling. When the room temperature is low, it can be put in a 37 ℃ water bath for 10-20 minutes, and the upper serum can be centrifuged for standby.
3. Golden head cover of inert separating gel accelerating tube
Inert separating gel and coagulant were added to the blood vessels. The samples remained stable within 48 hours after centrifugation. The coagulant can activate the coagulation mechanism and accelerate the coagulation process. The sample type is serum, which is suitable for emergency serum biochemical and pharmacokinetic tests. After collection, mix upside down for 5-8 times, stand upright for 20-30min, and centrifugate the supernatant for use.
4. Black head cover of sodium citrate ESR test tube
The required concentration of sodium citrate in ESR test is 3.2% (equivalent to 0.109mol / L), and the ratio of anticoagulant to blood is 1:4. It contains 0.4ml of 3.8% sodium citrate and draws blood to 2.0ml. This is a special tube for erythrocyte sedimentation rate. The sample type is plasma, which is suitable for ESR. After drawing blood, mix it upside down for 5-8 times. It needs to be shaken again when in use. The difference between it and the test tube for clotting factor test is that the concentration of anticoagulant and the proportion of blood are different, which should not be confused.
5. Light blue cap of sodium citrate coagulation test tube
Sodium citrate plays an anticoagulant role by chelating with calcium ions in blood samples. The concentration of anticoagulant recommended by the Standardization Committee of national clinical laboratory is 3.2% or 3.8% (equivalent to 0.109mol/l or 0.129mol / L), and the ratio of anticoagulant to blood is 1:9. There is about 0.2ml of 3.2% sodium citrate anticoagulant in the vacuum blood collection vessel, and the blood is collected to 2.0ml. The specimen is made of whole blood or plasma. After collection, it is immediately reversed and mixed for 5-8 times. After centrifugation, the upper plasma is taken for standby, which is suitable for coagulation experiment, Pt, APTT and coagulation factor examination.
6. Green cap of heparin anticoagulant tube
Heparin was added to the blood vessels. Heparin has the function of antithrombin directly, which can prolong the clotting time of sample. It is used in emergency and most biochemical experiments, such as liver function, kidney function, blood lipid, blood glucose, etc. It is suitable for red blood cell fragility test, blood gas analysis, hematocrit test, ESR and common biochemical test, not suitable for hemagglutination test. Excessive heparin can cause leukocyte aggregation and cannot be used for leukocyte count. Because it can make the background of blood piece stained light blue, it is not suitable for leukocyte classification. It can be used for hemorheology. The sample type is plasma. After blood collection, mix it upside down for 5-8 times immediately and take the upper plasma for standby.
7. Light green head of plasma separation tube
Adding heparin lithium anticoagulant into inert separation hose can achieve the purpose of rapid plasma separation, which is the best choice for electrolyte detection. It can also be used for routine plasma biochemical detection and emergency plasma biochemical detection such as ICU. It is used in emergency and most biochemical experiments, such as liver function, kidney function, blood lipid, blood glucose, etc. Plasma samples can be directly on the machine and kept stable for 48 hours under cold storage. It can be used for hemorheology. The sample type is plasma. After blood collection, mix it upside down for 5-8 times immediately and take the upper plasma for standby.
8. Gray head cover of potassium oxalate / sodium fluoride
Sodium fluoride is a weak anticoagulant, which is usually used in combination with potassium oxalate or sodium periodate. Its proportion is 1 part of sodium fluoride and 3 parts of potassium oxalate. 4mg of this mixture can make 1ml of blood not coagulate and inhibit the decomposition of sugar within 23 days. It can not be used for the determination of urea by Urease method, nor for the determination of alkaline phosphatase and amylase. It is recommended to be used for the detection of blood glucose. Contains sodium fluoride or potassium oxalate or EDTA two sodium (EDTA-Na) spray, can inhibit the activity of enolase in sugar metabolism, after blood collection and reverse mixing 5-8 times, after centrifugation, take the supernatant plasma reserve, is a rapid detection of blood sugar special pipe.
9. EDTA anticoagulation tube purple head cover
EDTA (molecular weight 292) and its salts are amino polycarboxylic acids, which are suitable for general hematological examination, and are the first test tube for blood routine, glycosylated hemoglobin and blood type examination. It is not suitable for coagulation test and platelet function test, nor for the determination of calcium ion, potassium ion, sodium ion, iron ion, alkaline phosphatase, creatine kinase and leucine aminopeptidase. It is suitable for PCR test. Spray 100ml of 2.7% EDTA-K2 solution on the inner wall of vacuum tube, blow dry at 45 ℃, take blood to 2mi, mix it upside down for 5-8 times immediately after drawing blood, and mix it for use. The sample type is whole blood, which needs to be mixed when it is used.