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Practical (BG,CT,BT) briefing corrected.pptx

  1. Clotting time, Bleeding time & Blood groups Practical session briefing
  2. Blood grouping • Also known as blood typing • PRINCIPLE • The surfaces of red cell membrane contain a variety of genetically determined antigens, called agglutinogens, while the plasma contains antibodies (agglutinins) • To determine the blood group of a person, his/her red cells are made to react with commercially available antisera containing known agglutinins • The slide is then examined under the microscope to detect the presence or absence of clumping and hemolysis (agglutination) of red cells which occurs as a result of antigen-antibody reaction
  3. • APPARATUS AND MATERIALS • Microscope • Dropper • Sterile blood lancet • Sterile cotton • Alcohol • Toothpicks • Glass slides • Normal saline • Anti-A serum (contains monoclonal anti-A antibodies) • Anti-B serum (contains monoclonal anti-B antibodies) • Anti-D serum (contains monoclonal anti-D antibodies)
  4. • Preparation of red cell suspension • Add two drops of blood with 2ml of saline in a small test tube • A suspension of red cells in saline should preferably be prepared and used instead of adding blood drops directly from the fingerpick to the antisera for the following reasons: • Dilution of blood permits easy detection of agglutination and hemolysis, if present. (Red cells in undiluted blood tend to form large rouleaux and masses. These may be difficult to disperse and may be mistaken for agglutination) • Plasma factors likely to interfere with agglutination are eliminated
  5. Put one drop of anti-A serum on the left half Put one drop each of normal saline on the right halves (C) Add a drop each of red cell suspension to both sides Mix the anti-sera and red cells, and saline and red cells Put one drop of anti-B serum on the left half Put one drop each of normal saline on the right halves (C) Add a drop each of red cell suspension to both sides Mix the anti-sera and red cells, and saline and red cells Put one drop of anti-D serum on the left half Put one drop each of normal saline on the right halves (C) Add a drop each of red cell suspension to both sides Mix the anti-sera and red cells, and saline and red cells
  6. • The red cells-saline mixture on the “control” sides of each slide will act as a control to confirm agglutination or no agglutination on the corresponding test side • Wait for 8–10 minutes, then inspect the 3 antisera-red cell mixtures (“test” mixtures) and ‘control ‘ mixtures, first with naked eye to see whether agglutination has taken place of not • Then confirm under low magnification microscope, comparing each “test mixture” with its corresponding “control mixture”
  7. • OBSERVATIONS AND RESULTS • i. If agglutination occurs, it is usually visible to the naked eye. The hemolysed red cells appear as isolated (separate), dark-red masses (clumps) of different sizes and shapes. • ii. There is brick-red coloring of the serum by the hemoglobin released from ruptured red cells. • iv. Under LP objective, the clumps are visible as dark masses and the outline of the red cells cannot be seen. • No agglutination in the ‘control’ mixtures
  8. BT and CT
  9. WHAT IS THE CLINICAL SIGNIFIC ANCE OF DOING BT AND CT? 1. History of frequent, persistent or spontaneous bleeding. 2. Before every minor and major surgery.(eg; tooth extraction) 3. Before taking biopsy (bone marrow, kidney, liver etc.) 4. Before and during anticoagulant therapy. 5. Family history of bleeding disorder.
  10. BLEEDIN G TIME First functional platelet evaluation test Introduced by duke in 1900 Used to detect defects in primary hemostasis Used as a screening test for vascular disorders as well as platelet function test
  11. REQUIMENTS A) Blotting papper B) Stop- watch C) Sterile Lancet D) Alcohol swabs
  12. PROCEDURE a) After following sterile precautions, prick the fingertip deep enough (2- 3 mm) to result in bleeding. Note the time of onset of bleeding. b) Apply a piece of filter paper to the blood-drop every 30 seconds until the bleeding stops. Note the time when no trace of blood on the filter paper c) Count the spots of blood on filter paper and express bleeding time in minutes and seconds. d) The bleeding time estimated by this method of a normal subject is within the range of 2-5 minutes. Normally, bleeding time by this methods range by 1-7minutes. A value exceeding 10 minutes is clearly abnormal.
  13. Results 6 x 30 sec = 180 sec
  14. CLINICAL SIGNIFICANCE •Normal Bleeding Time: 1 to 7 minutes Prolonged BT in Thromboctytopenia Disorders in platelet: -thrombasthenia,storage pool disease,Bernard –Soulier syndrome Afibrinogenemia Severe hypofibrinogenemia Vascular disorders Aspirin
  15. CLOTTING TIME WHOLE BLOOD CLOTTING TIME The time it takes for whole blood , drawn from a vein and immediately placed in a container to clot. It measures all stages of intrinsic coagulation It is not a very sensitive method Avoid contamination with tissue fluid.
  16. Aim: To determine Clotting time by capillary method. *The time from pricking the finger to the appearance of the fibrin clot is the clotting time
  17. REQUIREMENT 1. Glass capillary tubes ( Non heparnised ) 2. A Petri dish 3. Alcohol swabs 4. Cotton wool 5. Sterile lancet
  19. PROCEDURE a) Clean finger with aseptic alcohol swab. b) Prick the finger with lancet resulting in bleeding, note the time of onset of bleeding. c) Wipe away the first drop of blood, fill freely flowing blood is taken into a capillary tube up to about 8 cm long without air bubble, holding the tube horizontally let it fill by capillary action. d) Roll the capillary gently between the palms, Fill more than one tube. e) At the end of two minutes after making the puncture, break off 0.5cm of capillary tube (blood containing end) and separate the two halves slowly. f) Repeat the procedure at 30 second intervals with the remaining tubes. g) When the blood forms a continuous thread-like clot between the broken ends of the tube, the end-point has been reached, Note the time. h) Clotting time by this method is 3-8 minutes.
  20. RESULTS…. Normal Clotting Time: 3-8 minutes
  21. CLINICAL SIGNIFICANCE • Only severe clotting factor deficiency can be recognized. • Prolonged CT more than 10’-pt subjected to more detailed test. • Used to monitor heparin therapy. • Can be due to the deficiency of plasma factors such as Antihemophiliac globulin,plasma thromboplastin,fibrinogen,prothrombin. • Circulating anticoagulants