fibrin degradation products

Under the action of plasmin, fibrin (original) can be degraded to produce fragments X, Y, D, E and other fragments of different molecular weights, collectively referred to as fibrin (original) degradation products (FDP). Tests for determining the amount of FDP in plasma (or urine) are usually immunoelectrophoresis, immunodiffusion, flocculation, latex agglutination (Fi) test, erythrocyte agglutination inhibition test, staphylococcal aggregation test, reverse blood coagulation test, and Enzyme-linked immunosorbent assay and so on. Basic Information Specialist classification: examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Analysis results: Below normal: Normal value: Staphylococcal aggregation test: 0-2mg/L Above normal: negative: Normal when negative. Positive: Reverse hemagglutination test: increased FDP content, seen in primary and secondary fibrinolysis. Staphylococcal aggregation test: increased FDP content, same as reverse hemagglutination test. Tips: Before the examination, the diet is light and alcohol is prohibited. Check for an empty stomach in the morning. Normal value (1) Reverse hemagglutination test: less than 10 mg/L. (2) Staphylococcal aggregation test: the slide method is negative, and the test tube method is 0 to 2 mg/L. Clinical significance (1) Reverse hemagglutination test: FDP content increased, seen in primary and secondary fibrinolysis. (2) Staphylococcal aggregation test: FDP content increased, same as reverse hemagglutination test. Precautions (1) Reverse hemagglutination test: 1 Using different batches of sensitized red blood cells, the fibrinogen standard must be determined again. 2 Keep the plastic plate clean. 3 The same batch of sensitized red blood cells should be stored for too long, and the antibody titer may be reduced. (2) Staphylococcal aggregation test: 1 The serum to be tested should be fully coagulated and the serum separated in time. 2 Because the specimens such as pleural effusion and ascites contain fibrinogen, add the same amount of thrombin (10u/ml) before the test, incubate at 37 °C for 30 min, centrifuge, and take the supernatant test. Inspection process (1) Reverse hemagglutination test: 1 Take 1 ml of venous blood, place in a small test tube, incubate at 37 ° C for 1 h, and separate the serum. 2 "V" type hole plastic plate, the first hole began to the 12th hole, and each well was added with 25 μl of physiological saline. 3 The first well was added with 25 μl of the test serum, and the ratio was diluted from the second well. 4 Add 25 μl of sensitized red blood cells per well. The subsequent steps were prepared in the same manner as the standard curve. 5 standard curve preparation: A. A known amount of pure fibrinogen was diluted to 10 mg/L with physiological saline. B. On the "V" type hole plastic plate, 25 μl of physiological saline was added to each well from the second hole. C. The diluted fibrinogen solution was added to each of the first and second wells by 25 μl, and serially diluted from the second well to 0.078 mg/L. D. Take one sensitized red blood cell and make a suspension with 1 ml of physiological saline, and add 25 μl per well. E. Set the micro-oscillator, shake for 30s, place at 37 ° C, and incubate for 30 min. F. Place at room temperature for 20 min and observe the results. 6 calculation: A. Standard calculation: The fibrinogen dilution concentration is 10, 5, 2.5...0.0078 mg/L, and the sensitized red blood cells appear as the reaction end point without agglomeration. For example, the 7th hole is the end point, that is, the sensitivity of the antibody can detect fibrinogen to be 0.15625 mg/L. B. Specimen calculation: Find the end point of the agglutination, calculate the dilution factor, and then multiply 0.15625 mg/L by the dilution factor. (2) Staphylococcal aggregation test: 1 slide method: absorb 0.05ml of bacterial liquid application solution, 0.05ml of serum to be tested, mix it on the slide, shake the slide for 2min at room temperature, and observe whether the bacteria are clustered. There were agglomerates who were positive and no aggregators who were negative. At the same time, 0.05 ml of physiological saline was used instead of serum as a control. 2 test tube method: take 0.1ml of the test serum, diluted with physiological saline, then add 0.05ml of freshly prepared bacterial solution in each tube, shake 200 times / min for 2min, immediately add physiological in each tube 0.5 ml of saline was allowed to stand at room temperature for 30 min, and the results were observed. And compared with the control tube, if there is obvious bacterial aggregation, the last tube where aggregation occurs is used as the reaction end point. Not suitable for the crowd Special diseases: Patients with hematopoietic dysfunction, 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.

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