Several problems should be paid attention to in the use of vacuum blood collection tube
1. The patient should be relaxed during blood collection and the environment should be warm to prevent venous contracture. The time of tying the arm should not be too long, and it is forbidden to beat the arm, otherwise it may cause local blood concentration or activate the coagulation system. Making a fist for 2 minutes can increase the serum potassium concentration by 1.0 to 1.5 mmol/L. Blood collection should be precise to prevent tissue damage and exogenous coagulation factors entering the test tube and affecting the test results.
2. The blood volume for sample collection should be sufficient. The existence of vacuum can easily rupture blood cells. If insufficient blood samples are used, the cork should be opened for a while after blood collection. The ratio of blood to anticoagulant must be precise, and the absolute content of anticoagulant in the blood sample can change the calcium ion concentration in the plasma and thus affect the experimental results. The higher the absolute concentration of calcium, the shorter the coagulation time of PT and APTT.
3. When using blood collection tubes containing coagulant or separation gel, be sure to wait for the blood to coagulate before centrifuging, otherwise clots are likely to appear in the serum and cause the instrument to block holes. The serum tube (red) generally needs to wait for 0.5 to 1 hour, and the one containing the coagulant needs to wait for 10 to 30 minutes. After the heparin tube (green) is mixed and fully anticoagulated, the plasma can be separated by centrifugation, and the separation rubber tube (yellow) can be used for 5 to 10 minutes. Centrifuge after min.
4. The recommended order of blood collection is coagulation tube (serum tube) → sodium citrate tube → heparin or EDTA tube → potassium oxalate 2 sodium fluoride tube → erythrocyte sedimentation tube. The main reason is that the first tube often contains tissue fluid, which is easy to cause blood coagulation and is not suitable for blood coagulation measurement.
5. After the blood collection is completed, first remove the last test tube from the needle holder, and then pull out the needle from the vein. It is caused by the spring being too slow or not being able to spring back in place.
6. Due to the relatively large negative pressure of the vacuum tube, at the beginning of blood collection, the blood flow into the bottom of the tube is fast, and the collision of red blood cells can cause rupture, and hemolysis is occasionally seen in clinical practice. In this regard, when collecting blood samples, tilt the needle on the side of the blood collection tube of the bidirectional blood collection needle so that it is close to the side wall of the blood collection tube, and the blood flows down slowly along the tube wall, so as to avoid the direct impact of red blood cells and cause rupture and form hemolysis.
7. Because the latex sheath of the two-way blood collection needle is loose or the needle sticks out of the latex sheath, the two-way blood collection needle is not tightly sealed. During venipuncture, blood leaks along the end of the blood collection tube of the bidirectional blood collection needle. In this regard, check and fasten the latex sheath before blood collection. If the needle sticks out, reinsert the needle to maintain its airtightness.
8. Since the puncture needle is attached to the blood vessel wall or there is no negative pressure in the blood collection tube, the blood inflow is not smooth. On the premise of ensuring the success of venipuncture, adjust the direction of the needle until the blood flows into the blood collection tube. If it is invalid, replace the blood collection tube. .
9. Due to insufficient negative pressure in the blood collection tube, the blood collection volume is insufficient, the syringe needle can be pierced from the rubber stopper of the blood collection tube, and the air in the blood collection tube can be sucked to form a negative pressure to collect the blood sample. When the original blood volume is low, the blood collection tube can be replaced directly.
