Red blood cell osmotic fragility test

This test measures the resistance of red blood cells to various concentrations of hypotonic solutions. In hypotonic saline, water permeates through the cell membrane, causing the red blood cells to gradually swell and destroy. The permeability of red blood cells depends mainly on the ratio of surface area to volume of red blood cells. The surface area is large and the volume is small, and the resistance to the salt solution is large, and vice versa, the resistance is small (the brittleness is increased). The spherical red blood cell surface/volume ratio is reduced, which is particularly sensitive to hypotonic solutions, and the brittleness is significantly increased. Basic Information Specialist classification: cardiovascular examination classification: blood examination Applicable gender: whether men and women apply fasting: not fasting Reminder: The reagents are required to be accurately prepared. The reagents should be replaced once or twice a month. The concentration of NaCl can be increased due to evaporation of water. Normal value The Sanford method initially dissolves (starts hemolysis) 0.0042 ~ 0.0046 (0.42% ~ 0.46%) sodium chloride solution. Completely hemolyzed 0.0032 to 0.0034 (0.32% to 0.34%) sodium chloride solution. Clinical significance unusual phenomenon: (1) Increased hereditary spherocytosis, autoimmune hemolytic anemia, congenital hemolytic jaundice (familial hemolytic jaundice). (2) reduce sickle cell anemia, obstructive jaundice, iron deficiency anemia, thalassemia, lead poisoning, pernicious anemia, splenectomy, liver disease. Need to check the crowd: People with anemia, lead poisoning, jaundice, and abnormal liver. Precautions (1) There should be a normal control for each examination, and the difference between the normal control and the subject is 0.04%, which is clinically significant. (2) The reagents are required to be accurately prepared. The reagents should be replaced once or twice a month, and the NaCl concentration can be increased due to evaporation of water. (3) Prevent red blood cell damage when taking blood. (4) Anticoagulant Heparin should be used to remove fibrin blood, citric acid or oxalate, which can increase the ionic strength and affect the osmotic pressure. (5) If the results of the initial and complete hemolysis are difficult to judge, it can be observed after centrifugation. (6) The osmotic fragility of thalassemia is reduced, and a low concentration of NaCl solution should be examined. (7) For severe anemia, RBC should be formulated into 50% concentration, and jaundice should wash red blood cells. (8) Blood specimens should not be stored in the refrigerator for more than 6 hours. Inspection process 1. Prepare different concentrations of NaCl solution. Firstly configure 100ml of 1% hypotonic NaCl solution, then go to 12 clean tubes of the same diameter, numbered on the test tube rack, add 1% NaCl solution and distilled water to each tube according to the following table, mix and mix, configure 12 A hypotonic NaCl solution of different concentrations from 0.68% to 0.24%. 2. A 0.85% NaCl solution and a 1.9% urea solution were separately disposed. Take another 3 small tubes, numbered 13~15, respectively, containing 2.5ml of 0.85% NaCl solution. 1.9% urea solution and distilled water. 3, iodine, alcohol disinfection of the skin with a sterile dry, heparin-wet injector 2cm from the middle of the elbow vein, self-interested, 1ml of which was added to the test tube, the remaining blood added 1 drop to each of the 15 test tubes, Mix gently. 4. Observe the changes of the 13, 14, and 15 tubes. The remaining 12 tubes were allowed to stand at room temperature for 1 hour, and then the color and transparency of the mixture were observed. (1) The liquid in the test tube completely turned into a transparent red color, indicating that the red blood cells were all broken, and it was completely hemolyzed. (2) The lower layer of the liquid in the test tube is turbid red, and the upper layer is transparent red, indicating that part of the siphon packet is broken, which is called incomplete hemolysis. (3) The lower layer of the test tube is turbid red, and the upper layer is colorless and transparent, indicating that the red blood cells are not broken. 5. Record the test results. This includes the subject's name and the range of erythrocyte osmotic fragility (ie, the NaCl concentration of the minimum resistance and the NaCl concentration of the maximum resistance) and the results of 13-15 tubes. 6. Take 1 drop of each of the 6th tube and the 13th tube mixture onto the glass slide, cover the cover glass, and observe the red blood cell morphology under the microscope. Not suitable for the crowd No taboos. Adverse reactions and risks No complications.

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