blood smear

Blood smear is the basic method of blood cytology, and it is widely used, especially for the diagnosis of various blood diseases. However, poor preparation and staining of blood samples often make cell identification difficult and even lead to erroneous conclusions. For example, the blood film is too thick and the cells overlap and shrink, and the blood film is too thin. The white blood cells are mostly concentrated on the edge; the well-stained blood film is one of the main basic techniques of hematology examination. Basic Information Specialist classification: cardiovascular examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Analysis results: Below normal: Normal value: no Above normal: negative: A negative result of the test should be normal. Positive: Prompt infection or vascular disease. Tips: Pay attention to normal eating habits and pay attention to personal hygiene. Normal value The type and proportion of the flora in the body are normal, and the human body is in a state of dynamic balance and is negative. Clinical significance Abnormal result First, abnormal white blood cell morphology 1. The toxic changes of neutrophils are more common in severe infections and poisoning. Close observation of the number of white blood cells and the toxic changes of neutrophils have important clinical value in judging the degree of infection, patient resistance and prognosis. 2. Other abnormal changes of neutrophils (1) Giant multi-leaf nuclear neutrophils - more common in megaloblastic anemia. (2) rod-shaped bodies - mainly found in acute non-lymphocytic leukemia. (3) Other abnormal granulocytes are mostly genetically related abnormal morphological changes. 3. Heterotypic lymphocytes are more common in serious viral infections, allergies and poisoning. Among them, patients with fever, submandibular and cervical lymph nodes, increased white blood cells, and more than 10% of atypical lymphocytes are more likely to diagnose infectious mononucleosis. Some types of atypical lymphocytes can also be seen in some children's blood, but no more than 3%, no clinical diagnostic value. 4. Smear cells or basket cells, found in lymphocytic leukemia. Second, blood system diseases can affect the quality of red blood cells, especially in anemia patients, not only the number of red blood cells and hemoglobin concentration, but also the corresponding specific red blood cell morphology changes, manifested in red blood cell size, shape, dyeing properties and inclusions abnormal. The people to be examined include atypical lymphocytes, leukemia, abnormal granulocytes, megaloblastic anemia, lymphocytic leukemia, anemia and other symptoms. Positive results may be diseases: angular cheilitis, sepsis in the elderly, chronic benign neutropenia in children, chronic myeloid leukemia in children, acute myeloid leukemia in children, regression fever, secondary iron granulocyte anemia, pediatric alpha- Thalassemia, Marburg virus disease, systemic idiopathic telangiectasia precautions Forbidden before examination: Pay attention to normal eating habits and pay attention to personal hygiene. Inspection requirements 1. Cleaning of the slide: The new slide often has free alkali, so soak it in the cleaning solution or 10% hydrochloric acid for 24 hours, then wash it thoroughly. The used slides can be boiled in water of appropriate amount of soapy water or synthetic detergent for 20 minutes, then the soap and blood film are washed away with hot water, washed repeatedly with tap water, and then immersed in 95% ethanol for 1 hour if necessary. Then dry or bake dry. When using the slide, you can only hold the edge of the slide and do not touch the surface of the slide; to keep the slide clean, dry, neutral, and non-greasy. 2. Cell staining is very sensitive to the concentration of hydrogen ions. The slides must be chemically cleaned during the dyeing process. The preparation of Wright's dye solution must use high-quality methanol. The diluted dye solution must be buffered. The rinse water should be near neutral, otherwise various cells The staining reaction is abnormal, which makes the identification of cells difficult and even causes errors. 3, a good blood film, the thickness is suitable, the head body is distinct, the distribution is even, the edges are neat, and there are gaps on both sides. It is best to fix the stain immediately after the blood film is prepared to avoid cell lysis and degeneration. 4, the blood film is not dry, the cells have not been firmly attached to the slide, easy to fall off during the dyeing process, so the blood film must be fully dry. 5, dyeing time and dye concentration, room temperature level, how much cells. The lighter the dyeing solution, the lower the room temperature, the more cells, the longer the dyeing time required or the appropriate amount of dyeing liquid, so the dyeing time should be determined according to the specific conditions. Especially when replacing new dyes, it is necessary to try dyeing and explore the best dyeing conditions. 6, the dyeing liquid should not be too small, in order to prevent evaporation of dry dye deposited on the blood film is difficult to rinse. 7. Apply flushing water to wash the dye solution. Do not pour the dye solution first to prevent the dye from sinking on the blood. 8. If the dyeing is too deep, it can be decolorized by methanol or alcohol. It is best not to dye it. When it is necessary to dye it, the dye solution can be diluted first and then counterstained. 9, should pay attention to protect the blood film tail cells when dyeing, can not be crossed. Because larger cells often appear here. Inspection process Blood smear preparation and blood cell observation 1. Take one drop of blood at the end and place it on one end of the slide. Hold the slide on the left. The end of the right hand with a smooth edge pushes the blood drop from the front of the blood drop. The blood drops spread along the push piece, and then The angle between the pusher and the slide is kept moving forward 30-45 degrees, and the next thin film is left on the slide. 2. After the blood smear is made, the hand-held slide can be swung in the air to make the blood film dry quickly, so as to avoid blood cell shrinkage. 3, use a crayon to scribe on both sides of the blood film to prevent the dye solution from overflowing, then place the blood film on the staining rack, add 2-3 drops of Wright's dye solution to cover the whole blood film, fix 0.5-1.0 minutes. . Add equal or slightly more fresh distilled water and mix with the dye for 5-10 minutes. 4. Wash the dye solution with clean water. After it is naturally dried or blotted with absorbent paper, the blood smear can be placed under the microscope for microscopic examination. 5. White blood cell classification and counting. Not suitable for the crowd 1. Patients who have taken contraceptives, thyroid hormones, steroid hormones, etc., may affect the results of the examination and prohibit patients who have recently taken the drug history. 2, special diseases: patients with hematopoietic function to reduce disease, such as leukemia, various anemia, myelodysplastic syndrome, etc., unless the examination is essential, try to draw less blood. Adverse reactions and risks 1, subcutaneous hemorrhage: due to pressing time less than 5 minutes or blood draw technology is not enough, etc. can cause subcutaneous bleeding. 2, discomfort: the puncture site may appear pain, swelling, tenderness, subcutaneous ecchymosis visible to the naked eye. 3, dizzy or fainting: in the blood draw, due to emotional overstress, fear, reflex caused by vagus nerve excitement, blood pressure decreased, etc. caused by insufficient blood supply to the brain caused by fainting or dizziness. 4. Risk of infection: If you use an unclean needle, you may be at risk of infection.