Blood sample detection must be well known by all of us. Basically, many clinical research projects will be involved as indicators to evaluate safety. Some disease-related markers and specific tests will also be carried out through blood samples. Desheng would like to share with you the contents of blood sample collection and preservation.
Blood composition
Blood is mainly composed of plasma and blood cells (so-called blood cells). After the blood is treated with coagulant, it can be found that plasma and blood cells are obviously divided into two parts after centrifugation or standing for a period of time in a centrifuge. Blood cells are deposited at the bottom because of heavy weight, and the yellow transparent liquid suspended above the red blood cells is plasma.
If the blood is naturally coagulated without anticoagulant treatment, the blood will be divided into two parts. The three visible components of red blood cells, white blood cells and platelets are precipitated below; the clear and transparent light yellow liquid floating above is serum, which does not contain blood cells and fibrinogen.
Blood sample collection
1. (common serum tube) - red head cover, no additive in the blood collection vessel, used for routine serum biochemistry, blood bank (before blood storage, it is necessary to test various indicators of blood to determine whether it is qualified, the additive will affect the test results, so there is no additive in the blood collection vessel) and serological related tests.
2. (rapid serum tube) - orange red head cap, coagulant in the blood collection vessel, which can activate fibrin, change soluble fibrin into insoluble fibrin polymer, and then form stable fibrin clot. The rapid serum tube can coagulate the collected blood within 5 minutes, which is suitable for emergency serum series test.
3. (Inert separation gel coagulation accelerator tube)-golden head cap, inert separation gel and coagulant added in the blood collection tube After the specimen is centrifuged, the serum separating gel can completely separate the liquid components (serum or plasma) and the solid components (red blood cells, white blood cells, platelets, fibrin, etc.) in the blood and completely accumulate in the center of the test tube to form a barrier. The specimen is within 48 hours keep it steady. A coagulant can quickly activate the coagulation mechanism and accelerate the coagulation process, and is suitable for emergency serum biochemical tests.
4. (heparin anticoagulant tube) - green cap, with heparin added into the blood collection vessel. It is suitable for hemorheology, red blood cell fragility test, blood gas analysis, hematocrit test and ordinary biochemical test. Heparin has the function of antithrombin and can prolong the clotting time of samples, so it is not suitable for hemagglutination test. Excessive heparin can cause leukocyte aggregation and cannot be used for leukocyte count.
5. (plasma separation tube) - light green head cover, adding heparin lithium anticoagulant in inert separation tube, can achieve the purpose of rapid separation of plasma, is the best choice for electrolyte detection, can also be used for routine plasma biochemical determination and ICU and other emergency plasma biochemical detection. The plasma samples can be directly put on the machine and kept stable for 48 hours under cold storage.
6. (EDTA anticoagulant tube) - Purple head cap. The anticoagulant is ethylenediaminetetraacetic acid (EDTA). It can combine with calcium ion in blood to form chelate, which makes Ca2 + lose coagulation and prevent blood coagulation. It is suitable for many kinds of hematological examination. However, EDTA can affect platelet aggregation and is not suitable for coagulation test, platelet function test, calcium ion, potassium ion, sodium ion, iron ion, alkaline phosphatase, creatine kinase and PCR test.
7. (sodium citrate coagulation test tube) - light blue head cap. Sodium citrate acts as anticoagulant mainly by chelating with calcium ions in blood samples. It is suitable for coagulation test.
8. (sodium citrate ESR test tube) - black head cover. The concentration of sodium citrate required for ESR test is 3.2% (equivalent to 0.109 mol / L), and the ratio of anticoagulant to blood is 1:4.
9. (potassium oxalate / sodium fluoride) - gray head cover, sodium fluoride is a weak effect anticoagulant, usually combined with potassium oxalate or sodium ethyliodate, its ratio is 1 phr sodium fluoride, 3 phr potassium oxalate, it is a good preservative for blood glucose determination, can not be used for urea determination by Urease method, nor for alkaline phosphatase and amylase determination, it is recommended for blood glucose detection.
Handling and storage
The treatment of blood samples needs to be carried out according to the plan or the central laboratory manual. In this link, special attention should be paid to the different treatment conditions of blood samples, such as: blood routine can not be centrifuged; blood that can be stored for a long time, such as PK blood, must record the temperature record of the refrigerator, and always record the temperature log for all blood samples to ensure that the refrigerator thermometer is within the validity period
