Blood cell analyzer, clinical also known as blood analyzer or hemocytometer, blood cell counter.
The blood cell analyzer is one of the very widely used instruments for clinical testing in hospitals. Previously, the most primitive means of routine blood test is through the microscope manual microscopy, with the development of basic medicine, the application of high science and technology, blood cell analyzer has become an important means to replace the microscopy for routine blood analysis, especially with the classification of blood cell analyzer. (XFA6000Intelligent intelligent automatic blood cell analyzer)
Blood cell analyzer performance characteristics:
I. Performance characteristics:
1, now the blood cell analyzer are using the most advanced international technology of the silk rod drive, to avoid the traditional transmission (such as belt drive) by the ambient temperature of the shortcomings of the impact, make quantitative more accurate and more durable. It makes the quantification more accurate and durable.
2, in the white blood cell three classified histogram and red blood cell, platelet histogram on the identification of the boundary mark, intelligent automatic boundary mark identification line to make the analysis results more accurate.
3, the international leading dual-core embedded digital circuit system, to provide powerful and stable control and analysis capabilities.
4, data analysis using large-scale integrated telephone (ARM) technology to provide the most stable analysis results.
5, one-key operation or handwritten input information, XFA6000Intelligent will automatically inhale the blood specimen for dilution, analysis, and accurately provide 19 parameters and 3 histograms of 22 test results, Chinese language interface, 1 million results of the storage (including histograms), and a true-color 8-inch TFT screen display, the built-in thermal printer automatically prints. It makes the operation process very easy.
6, fully enclosed puncture sampling, effectively avoiding the risk of biological contamination of the operator; with 18 sampling position, can fully meet the test large-scale testing work, and has an emergency insertion function, XFA6000Intelligent will help your laboratory to create unprecedented efficiency and results.
Two, routine maintenance is very simple:
Before the test, just turn on the power button, you can complete all the preparatory work, including computer self-test, flushing, perfusion channel and blank value confirmation. After the test, press the off button XFA6000Intelligent can automatically flush all channels, and then automatically shut down to realize intelligent maintenance.
Three, intelligent blocking design:
XFA6000Intelligent's detection part of the use of ruby material, small hole aperture precision, and smooth and not easy to adhere. It is also equipped with the function of monitoring the blocked holes, and the positive and negative pressure flushing and electronic cauterization can be carried out to eliminate the blockage through the blockage removal program.
Four, safety and environmental protection:
Since the XFA6000Intelligent uses cyanide-free reagents to detect hemoglobin, it eliminates the need for troublesome waste disposal. The automatic cleaning function of the inner and outer walls of the injection needle gives the operator safety and security. The luxurious and humanized exterior design will make your testing environment more comfortable and safe.
What should be paid attention to in doing routine blood tests in order to better collect blood and facilitate the blood cell analyzer to analyze the results?
One, the collection of specimens
In order to obtain accurate and reliable test results, it is necessary to obtain high-quality specimens. High-quality specimens are the first step in high-quality testing. Ensure that the blood specimens in the complete form of the cells is the most basic requirements as a routine blood test with high-quality specimens. The preparation of blood cell test specimens is divided into two steps: collection and anticoagulation.
1. Specimen collection
The most common ways to obtain blood specimens for routine blood tests are venous blood collection and peripheral capillary blood collection according to the different sites of blood collection. Various literatures have shown that venous blood samples are the most reliable specimens, and finger blood is the least different from venous blood in peripheral capillary blood samples and more stable blood samples. Some studies have shown that finger blood is still less accurate and reproducible than venous blood: white blood cell counts are significantly higher (+8%) and platelet counts significantly lower (-9%). Therefore, the vast majority of experts recommend that venous blood should be used for routine blood tests and especially for the application of hematology analyzers.
2. Anticoagulation of specimens
Blood samples used for routine blood tests must be anticoagulated by anticoagulants. Among the many anticoagulants currently available, EDTA salts (EDTA-Na2, EDTA-K2, and EDTA-K3) are anticoagulants that have a relatively small effect on the morphology of leukocytes and platelets, which are the most suitable for routine blood tests. In addition to the influence of blood collection factors (physiologic factors, site of blood collection, etc.), in most cases the quality of the blood sample depends on the ratio of blood to anticoagulant. When the ratio of blood is too high, due to the relative lack of anticoagulant, the possibility of microclots in the plasma increases, and when used in hematology analyzers, the microclots may block the instrument and affect some of the test parameters at the same time. The ratio of blood is too low, and the relative excess of anticoagulant can have a serious impact on the test indexes. After the blood is anticoagulated by EDTA, the morphology of leukocytes will be changed, and this change is related to time and EDTA concentration.The optimal concentration of EDTA (compared with blood) is 1.5mg/ml.If the blood sample is low and the concentration of EDTA is up to 2.5mg/ml, the neutrophils are swollen, lobulated and disappeared, and the platelets are swollen, disintegrated, and produce fragments with the size of normal platelets.All of these changes will give erroneous results in routine blood tests and blood cell counts. This is especially important when using an automated blood cell analyzer.
Both venous and peripheral blood can be anticoagulated with an anticoagulant into a whole blood specimen (a specimen that does not contain diluent or that has minimal effect on the dilution caused by the specimen), and it is clear that it is very difficult to achieve the proper ratio of blood to anticoagulant in an anticoagulated specimen of peripheral blood. Therefore, most experts recommend that it is very difficult to prepare whole blood ratios. Therefore, most experts recommend vascular collection of venous blood.
Whether microscopic, or using a blood cell analyzer, since most dilutions of the specimen contain anticoagulants, trace amounts of venous or peripheral blood (10-40 μl) can be added directly to a certain amount of diluent to prepare what is commonly referred to as a pre-diluted specimen. In most cases, the preparation of pre-diluted specimens is applicable to peripheral blood samples.
The dilution of specimen
Blood is a red viscous suspension composed of blood cells and plasma. In the blood cell test counting, direct blood counting is difficult, whether it is microscopic examination or with a blood cell analyzer, the blood needs to be diluted appropriately and accurately in order to carry out the blood cell test counting. Based on the basic principles of blood cell analyzers, dilution factor and counting capacity are one of the most important design indexes in the design and application of blood cell analyzers. If the dilution factor is too low, it will form the overlapping defect of cell queuing through the sensor; if the dilution factor is too large, it will cause the number of blood cells within a certain measurement capacity to be too small, which will seriously affect the measurement accuracy of blood cell test.
Third, the specimen storage
Anticoagulant due to the time and concentration of the different, will cause the impact on the morphology of blood cells. Some studies have shown that anticoagulation of venous blood specimens with EDTA, within 5 minutes or 30 minutes after specimen collection, and testing within 8 hours (at room temperature) gives the best results. If accurate data on platelet and leukocyte classification are not required, specimens can be deposited at 2°C-8°C for up to 24 hours.
Prediluted specimens generally need to be measured within 10 minutes of specimen preparation; if cell stabilizers are added to the diluent, prediluted specimens should not be stored for more than 4 hours.
In short, there are many factors affecting the results of routine blood tests, and in order to obtain accurate test data, it is necessary to strictly follow the operating procedures in each step of the experiment. The content of this article is only a part of the summary of the routine blood test precautions, there may be shortcomings and defects, or please always in the clinical inspection of the front line of the work of the teachers to criticize and correct.
Four, blood cell analyzer counting method:
Counting the number of cells, fast, easy to standardize, counting accuracy is high, suitable for large-scale population health screening, but need special instruments. Certain human factors (e.g., inadequate anticoagulation), pathological conditions (e.g., presence of nucleated red blood cells, giant platelets, platelet clumping, etc.) can interfere with white blood cell counts. The instrument must be calibrated according to the NCCLS method before use, and routine quality control must be carefully adhered to.
V. Blood analyzer method of red blood cell counting detection principle:
Blood cell analyzer method: with electrical impedance and (or) light scattering principle.
The four major attributes of the blood cell analyzer to explore
The blood cell analyzer, also known as hemocytometer, hematology analyzer - is now the medical field of the common use of medical equipment, the use of blood cell analyzers greatly improve the quality and efficiency of the clinical blood tests. However, this kind of high-tech medical instruments in the identification of blood cell morphology and structure is not perfect, at present can only be used as a means of screening whole blood cell analysis. When in doubt, the blood film must be reviewed under the microscope, and the report can only be issued after confirmation, correction or supplementation. Otherwise, it is easy to cause missed diagnosis and misdiagnosis. Regarding the standard of review, the existing medical testing textbooks and operating procedures are not clearly discussed. For this reason, according to our practice and experience, and combined with the relevant literature at home and abroad, its standards, content, methods and other preliminary discussions.
1 The standard of review
There is no uniform standard for the review under what circumstances. Some people propose that as long as the blood cell analyzer gives a warning signal (FLAG), the review should be conducted, and this approach is too broad for the scope of the mastery. For example, if a patient with acute blood loss due to trauma has a low signal of red blood cells and hemoglobin given by the blood analyzer, it is not necessary to review the blood film for this purpose. In discussing film review criteria, Dotson suggests that each laboratory should define its own review parameters, histograms, or scatter plots, and that the presence of an instrument fuction or interpretive fuction figures from the blood cell analyzer should be considered as an indication that the analyzer is functioning well. The presence of instrument figs or interpretive flag messages is one of the conditions for review, but it should be considered in the context of the status of the blood cell analyzer and the patient's condition.
2 Content of the review
Many people think that the review is just to classify the white blood cells, but it is not. The review should include observation of the morphology of red blood cells, white blood cells and platelets; estimation of the platelet or white blood cell count (to confirm whether it is consistent with the data given by the instrument); observation of platelet aggregation or red blood cell aggregation, as well as the presence of abnormal cells with special morphology and parasites.
3 Requirements for reviewers
The reviewers of the blood film must be professionally trained, have basic and clinical knowledge of blood cell morphology, and be familiar with the blood cell analyzer, especially those who are familiar with the normal and abnormal patterns of histograms and scatter plots, and who are able to interpret and assess the significance of the abnormal patterns.
The reviewer should first carefully read the various parameters, histograms, scatter plots, and signals given by the analyzer. An initial impression of possible hematologic abnormalities or technical influences, etc., is gained. At the same time, the focus of the review is determined by the patient's clinical situation, including the initial diagnosis.
The blood is mixed well, pushed into a blood film and stained as soon as possible. EDTA anticoagulated blood smears differ from direct smears of skin puncture blood in a number of differences in cellular morphology; in addition, anticoagulated blood is most often stored for some time outside of the body, and this can have an impact on cellular morphology.
4 Methods of review
First, observe the blood film with low or high magnification to understand the distribution of blood cells, platelets or red blood cell aggregation (strings, piles), and the tail with large, piles of abnormal cells, etc.; continue to use oil microscope to browse the blood film in the middle of the thickness of the smear, and carefully observe the morphology of the red blood cells, leukocytes, and platelets and estimate the number of them. If the observation result is consistent with the report of the instrument, no additional test is needed, and the report can be issued according to the result of the instrument.
If a patient with anemia or other blood disorders has abnormal red blood cell counts and related indices (e.g., MCV, MCH, MCHC), red blood cell volume distribution width (RDW), histograms, or scatter plots, the focus should be on observing the size of the red blood cells, their morphology, their inclusions, their coloration, their size consistency, and the presence or absence of nucleated red blood cells. Any abnormalities should be described and reported. Due to the long storage of blood outside the body or other technical reasons during the smear, sometimes some false target-shaped red blood cells, mouth-shaped red blood cells and false spherical red blood cells may appear in localized areas of the blood film, and inexperienced examiners often treat them as real abnormal red blood cells. The easiest way to identify them is to look at other areas of the smear, and if they are true anomalous cells, the same abnormality can be seen throughout the entire smear (rather than in individual areas).
If the platelet count and histogram, mean platelet volume (MPV) are abnormal, and platelet width of distribution (PDW) is increased, the first step in viewing the smear is to estimate the platelet count, which, according to Willians et al, is normally about 8 to 15 platelets per oil microscope field of view in the zone of moderate thickness of the smear (in which each erythrocyte is in contact with, but does not overlap with, each other); or One platelet for every 10-30 red blood cells. Of course, this is only a rough estimate [2]. In our experience, it is not difficult to estimate the number of platelets by browsing through the blood film, and at the same time, pay attention to the morphology of the platelets, as long as you have been observing carefully and have accumulated some experience.
If the white blood cell count or histogram is abnormal, first review the blood film to estimate the number of white blood cells and look for na?ve or abnormal white blood cells. If discrepancies with the instrumental report or other abnormalities are found then a microscopic leukocyte classification count is performed. The general hematologist seems to be familiar with the classification of leukocytes. But to make accurate classification, there are still a lot of difficulties, individual cell classification standards, has not been completely unified.
In the routine classification of peripheral blood leukocytes, it is sufficient to classify granulocytes as neutral, eosinophilic and basophilic. Sometimes, in order to assist in the diagnosis of infections and hematologic diseases, clinicians require that neutrophils be further subdivided into lobulated nuclei, rod-shaped nuclei, late juvenile granulocytes, and mesophilic granulocytes. Distinguishing between rod and lobulated nuclei has been a persistent problem for the medical laboratory community. Historically, different definitions of rod nuclei have resulted in widely varying percentages of rod nuclei being reported, with reference values ranging from 0-5% to 12-18%. For this reason, the Clinical Pathology Association of the United States (CAP) recommends the following definition: "Mature granulocytic leukocytes with curved, banded nuclei without threadlike filament formation between the nuclear lobes are termed rod-shaped nuclei; if chromatin is present in the bridge connecting the nuclear lobes, this bridge is not considered to be a filament, but also is rod-shaped nucleus"; "If the nuclei are twisted (twist) and entangled, causing one part of the nucleus to press on top of the other, so that the shape of the whole nucleus cannot be seen, it should be judged as a lobulated nucleus." This recommendation has been adopted by the American Committee for Standardization of Clinical Laboratories. According to this standard, the reference value for rod-shaped nucleoli should be 5% to 10% [3]. However, despite this standard, contradictions and inconsistencies still exist in practice due to the different judgments and interpretations of individual examiners. Each laboratory should carry out quality control according to a uniform standard.
It is well known that lymphocytes in peripheral blood are a highly heterogeneous class of cells. Under the stimulation of antigens such as viruses and toxins, some of them will undergo proliferation and transformation to plasma cells or na?ve cells (mother cells), which leads to diverse morphological changes. For example, the cell size increases; the cytoplasm becomes more abundant, the blue stain deepens, and some contain vacuoles; the nucleus is irregularly shaped, and the chromatin becomes sparse, with occasional vaguely visible nuclear divisions. However, if the lack of extensive clinical experience may be mistaken for leukocyte na?ve cells.
The review of peripheral blood film is simple, but highly technical and based on the subjective judgment of the examiner. An excellent test workers should be based on the patient's clinical manifestations, blood histogram carefully blood film review, and comprehensive analysis, can make a variety of common anemia, leukemia, infections and other diseases in a timely manner, preliminary, and even a clear diagnosis.