1 Attention to the daily maintenance of the instrument, maintenance, so that the instrument is in the best working condition. o Before going to work, after work, first of all to do a good job of indoor hygiene, into the laboratory to change shoes, unrelated personnel are not allowed to enter the laboratory, to minimize the contamination of dust. o The operator of the instrument manual should be carefully read, the principle of the operating procedures, the meaning of the histogram of cell distribution, the meaning of abnormal alarms, causing the pollution of the blood cell analyzer. Operators of the instrument manual to read carefully, the principle of the instrument, operating procedures, the use of precautions, the significance of the histogram of cell distribution, the meaning of the abnormal alarm, the factors that cause experimental error and maintenance of the instrument to have a full understanding of the business knowledge should be solid, skillful operation, and work with a strong sense of responsibility. The choice of anticoagulant is also a very important factor, different anticoagulants have different results (Table 1) directly affect the results of the instrument. Through the experiment, heparin, bis-oxalate, sodium citrate can not be used as anticoagulant in blood cell analyzer. EDTA-K2, EDTA-K3, EDTA-Na2 as the anticoagulant of blood cell analyzer is more ideal, does not affect the number and size of white blood cells, the morphology of the red blood cells also has a minimal impact, and can inhibit platelet aggregation.EDTA-Na2 is inexpensive, but its solubility is low, and is not suitable for use as an anticoagulant in a small test tube, because the small test tube can not be adequately mixed and easily cause blood coagulation (in the test tube). EDTA-K2 and EDTA-K3 have high solubility and do not cause blood coagulation, so we apply EDTA-K2 or ED-TA-K3 as anticoagulant for hematology analyzer in our daily work, and the general dosage is 1.5-2mg of anticoagulant which can make 1ml of blood not to be coagulated. The blood collection containers we use are vacuum blood collection system, the blood and anticoagulant are fully mixed, and the blood samples are free of clots, which not only automate the blood analysis, but also ensure the quality control and the safety of the operators. The results are usually checked within 4 hours after blood collection. The reagents used must be qualified, we use the reagents matching the instrument, including diluent, hemolytic agent, cleaning solution and so on. If you use domestic production or homemade reagents, its conductivity, osmolality, pH, histogram and other major technical indicators as far as possible and imported matching reagents, in order to ensure the accuracy of the instrument determination.
2 Quality control in the experiment
Every day after the instrument is turned on, the instrument carries out self-check, and firstly conducts the reagent blank counting, which requires WBC=0, RBC=0, PLT<5×109/L, HB=0. When it is normal to use the original manufacturer's supporting quality control substances for determination, and the specimen can be measured only in the quality control range. The quality control procedure of blood analyzer is shown in Figure 1.We purchased the original instrument factory or the nationally approved laboratory's fixed value, and drew the routine work quality control chart every day to monitor the quality of work. Taking the measurement result as the vertical coordinate and the date of measurement as the horizontal coordinate, we first set the center of the vertical coordinate as the target value (T), and made a straight line parallel to the horizontal axis from this point, which was called the target value line. Then set the warning limit of the permissible error and the maximum permissible limit of the upper and lower four points respectively on the vertical axis, and then make four straight lines equal to the target value line through the four points, which are called the warning limit and the maximum permissible limit. Every day after the start, the first measurement of a fixed value specimen, requiring all the value of the fixed value of the object should fall within the maximum allowable range before the specimen is measured. Sometimes we use a normal human specimen every morning, repeat the measurement 5 times, take the average value as the target value, as a quality control material. When 15-20 specimens were measured, the QC was repeated once to compare with the target value, and the following rules were used to decide whether the control was out of control: WBC±0.3×109/L, HB±2g/L, MCV±2fL, MCH±1.5pg, MCHC±1.5%. Any up and down fluctuations more than the above range is out of control, this method is more simple and easy to implement.
3 Post-experimental quality control
On the basis of the previous work to play the patient's results are accurate and reliable, whether there is a blockage of the holes, the accuracy of the amount of suction, the dilution of the instrument, etc., the review of the report results is very important to determine the need to repeat the examination or manual operation is the last pass of the quality control.1 look at the graphs, the curve shape of the location. Look at the white blood cells and platelets to determine the presence of platelet clots, look at the platelet graph to determine the presence of interference, contamination, red blood cell destruction. o Batch of labs to look at the patient specimens on the day of the average value of the values should be kept within a certain range. o Batch of labs to look at the patient specimens on the day of the average value of the values should be kept within a certain range. Look at the total number of white blood cells, red blood cells, platelets, combined with the diagnosis, the results of a comprehensive judgment of the correct or incorrect. Whether all three are low because of insufficient suction or dilution error. Microporous is the key part of the blood cell analyzer, but also the most prone to clogging failure. When the instrument is half clogged, the result will be much lower, in this case, the instrument does not have any indication, and the half clogging of the microtiter wells is completely dependent on the operator's judgment. The white blood cell chart should be analyzed against the total number and the classified value, and the specimen can be smeared for microscopic examination if necessary. Comparison of red blood cell and platelet counts, through the mutual reference to determine the credibility of the two values: RBC high or normal, low PLT is credible; RBC, PLT are low suspected of clogging; RBC low, PLT high or normal suspected to look at the diagnosis. We can explain all the abnormal indications in each report, and the whole lab sheet should be consistent with the diagnosis. The cell histogram not only provides diagnostic data to the clinic, but also provides the operator with the monitoring of the working status of the instrument and the credibility of the experimental results. The histogram must be carefully analyzed to determine whether microscopic examination is required before issuing a report, which is even more important in the case of cell sorting and counting.