(1) measurement principle
Erythrocyte sedimentation rate (ESR) is a commonly used clinical test index. Blood samples are collected in a red blood cell sedimentation tube containing anticoagulant, and then placed vertically on the sample rack of the instrument. Under the action of gravity, red blood cells will gradually sink, leaving a transparent plasma on the upper part of the erythrocyte sedimentation tube. The instrument uses a pair of infrared transmitting and receiving tubes (TX-RX) to move up and down to measure the interface between red blood cells and transparent plasma, which can measure the dynamic sedimentation of red blood cells in a certain period of time.
(2) Measurement method
According to the reading principle of ESR analyzer, the moving range of the infrared transmitter-receiver tube (TX-RX) is C, and the reading terminals of the ESR tube are L at the bottom and H at the top.
In the process of the infrared transmitting and receiving tube moving from the lowest end (L) to the highest end (H), if the infrared ray cannot reach the receiving tube, it means that the infrared ray is blocked by high-density red blood cells. Once the infrared ray can pass through the erythrocyte sedimentation tube and reach the receiving tube, the signal of the receiving tube tells the computer to start calculating the distance needed to reach the mobile terminal.
L 1 indicates the height of blood in the erythrocyte sedimentation tube at zero time (initial height of blood sample), L2 indicates the height of erythrocyte sedimentation surface in the erythrocyte sedimentation tube at 30 minutes, L3 indicates the height of erythrocyte sedimentation surface in the erythrocyte sedimentation tube at 60 minutes, and k indicates the height of blood in the erythrocyte sedimentation tube when the infrared transmitting and receiving counter tube moves to the bottom. K is determined by the system of ESR analyzer itself and set in the computer.
If 1.6ml anticoagulated whole blood is continuously put into the sedimentation tube, the blood height in the sedimentation tube will change slightly due to different sample tubes. In order to compensate for this change, the initial height value is considered in a certain height range in ESR analyzer, and these changes are corrected by using the percentage principle of settlement.
(3) reading principles
The detection board composed of infrared photocells is selected to monitor 30 ESR tubes vertically simultaneously. The interval of vertical detection is 0. 16mm to read a data (i.e. the resolution of the instrument), and the detection period is 3 minutes. When the erythrocyte sedimentation tube is inserted into the instrument, the instrument automatically detects the erythrocyte sedimentation tube. The "0" timing as time timing is detected for the first time, and the blood height in the blood sedimentation tube is preliminarily judged and analyzed based on this. The acceptable range of the blood height m set by the instrument is 50 mm-64 mm (from the bottom of the sedimentation tube), and the recommended height is 55mm (corresponding capacity is 1.6ml, that is, 0.32ml anticoagulant, 65438). The height of blood in the ESR tube is beyond the acceptance range of the instrument, and the instrument refuses to detect the ESR tube. The blood height of ESR tube is within the acceptable range, and the instrument detects ESR tube. The whole test 10 for 30 minutes and 20 for 60 minutes.
(4) sample preparation
Each sample of ESR instrument needs 1.28ml of whole blood, and the blood of the sample to be tested can be directly injected into the ESR tube. At present, sedimentation tubes with negative pressure are usually used, and 0.32ml of anticoagulant has been injected into each sedimentation tube in advance, so in order to ensure that the blood to be measured in the sedimentation tube has a suitable volume, there is a marker line on the sedimentation tube. When blood is injected into the blood sedimentation tube, the total height of anticoagulant and blood reaches 3 mm near the marking line on the blood sedimentation tube, and the blood sedimentation tube is slowly inverted for 5-7 times to make the anticoagulant and blood mix evenly. Be careful not to have bubbles during anticoagulation.