Clotting Time & Bleeding Time PDF

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Exercise NO. 18 BLEEDING TIME Objectives: At the end of this exercise, the student is able to: 1. Discuss the principle of bleeding time. 2. Enumerate factors that may cause the bleeding time to prolong. 3. Enumerate and differentiate the methods of bleeding time. BLEEDING TIME An in vivo measuremen...

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Exercise NO. 18 BLEEDING TIME Objectives: At the end of this exercise, the student is able to: 1. Discuss the principle of bleeding time. 2. Enumerate factors that may cause the bleeding time to prolong. 3. Enumerate and differentiate the methods of bleeding time. BLEEDING TIME  An in vivo measurement of platelet participation in small vessel hemostasis.  A screening test for detecting disorders of platelet function and von Willebrand's disease.  Is directly affected by the platelet count and the ability of the platelet to form a plug.  The purpose of the bleeding time is to provide a measure of the platelet function in small vessel hemostasis. A prolonged bleeding time does not in itself diagnose underlying platelet disoders, either qualitatively or quantitatively. It indicates the need for a more quantifiable test. 

Prolonged bleeding time will result in the following:  When the platelet count is lower than 30,000-50,000/uL  Dysfunctional platelet  Von Willebrand's disease  Ingestion of aspirin-containing compounds, anti-inflammatory drugs, anticoagulants and some antibiotics.

METHODS: A) DUKE'S METHOD  Materials:  70% alcohol  sterile gauze  disposable blood lancet  filter paper  watch  Procedure: 1. Disinfect the site of puncture with 70% alcohol. 2. Puncture to a depth of 3mm with a sterile disposable lancet. 3. Start timing immediately after the skin puncture then use the filter paper to blot the drop of blood every 30 seconds. 4. Stop the time as soon as the bleeding stops. 5. Normal value: 2-4 minutes

B) IVY'S METHOD  Reagents and Materials:  70% alcohol pad  Sphygmomanometer  Stopwatch  Filter paper (2-3 sheets)  Sterile gauze  Procedure: 1. Position the patient's arm with the volar surface exposed. 2. Select a site avoiding surface veins, bruises, and edematous areas. 3. Place the sphygmomanometer on the upper arm. 4. Cleanse the test area with 70% alcohol pad and let air-dry. 5. Inflate the cuff to 40 mmHg and hold at this exact pressure for the duration of the test. The time between inflation and incision should be 30 to 60 seconds. 6. Open the sterile package and gently rest the Surgicutt surface on the patient's forearm. 7. Apply minimal pressure so that both ends of the instrument lightly touch the skun. 8. Gently push the trigger, starting the stopwatch simultaneously. 9. Remove the Surgicutt immediately after triggering. 10. After 30 seconds, wipe the flow of blood with the filter paper. (Bring the paper close to the incision, but do not touch the paper directly to the incision, so as not to disturb the formation of the platelet plug) 11. Wipe the blood every 30 seconds thereafter, until no blood stains the paper. 12. Stop the timer when only clear fluid is absorbed onto the filter paler. The bleeding time is determined to the nearest 30 seconds. 13. Release the pressure of the sphygmomanometer. 14. Record the bleeding time. 15. Normal value: 1-7 minutes C) COPLEY-LALITCH IMMERSION TEST  Materials:  70% alcohol sponge  Sterile gauze  Automatic lancet  Beaker of NSS  37 degrees C water bath  Stopwatch

Sheen. MT1144. HEMA LAB

 Procedure: 1. Disinfect the finger with 70% alcohol. 2. Puncture to a depth of 6mm. 3. Immediately start the timer. 4. Immerse the punctured finger in a beaker of NSS prewarmed at 37 degrees C water bath. 5. Observe for flowing out of red blood against the colorless NSS. 6. Stop timer as soon as blood stops flowing out. D) ASPIRIN TOLERANCE TEST (QUICK'S TEST)  NOTE:  4 tablets are enough to prolong the bleeding time of a normal individual.  2 tablets are enough to prolong the bleeding time of a patient with von Willebrand disease and thrombasthenia.  Patient should abstain from aspirin derivatives at least 3 days before the test.

B) CAPILLARY TUBE METHOD 1. Dale and Laidlaw's method 2. Sabraze's method

 Procedure: 1. Determine patient's 1st bleeding time using the Duke's method. 2. If bleeding time is more than 6 minutes, don't do the test anymore. 3. Give the patient 2 tablets of aspirin and a glass of water. 4. Determine patient's 2nd bleeding time using Duke's method after 2 hours. 5. Normal value: Difference between 1st and 2nd bleeding should not be more than 2 minutes.

MISCELLANEOUS LABORATORY TESTS FOR EVALUATING THE COAGULATION SYSTEM

A) SLIDE METHOD or DROP METHOD  Materials:  70% alcohol  Sterile gauze  Sterile disposable lancet  Stopwatch

 Procedure: 1. Disinfect the site of puncture with 70% alcohol. 2. Puncture to a depth of 3mm. 3. Wipe off the 1st drop of blood. 4. Start the timer as soon as the 2nd drop of blood appears. 5. Transfer to a clean glass slide three separate drops of blood. 6. Observe for clot formation or coagulation by using the lancet to check for fibrin threads in the blood. This appear as a "threadlike" substance that clings to the tip of the lancet. 7. Record the time when the 1st fibrin thread was formed. 8. Normal value: 2-4 minutes.  Precautions: 1. Observe time accurately. 2. Do not perform both tests on one finger. 3. Blot with filter paper only within the timed interval.

 Materials:  70% alcohol  sterile gauze  disposable blood lancet  filter paper  watch  2 tablets aspirin  1 glass of water

I. CLOTTING TIME

 Clean glass slide  Needle

 Materials:  70% alcohol  Sterile gauze  Sterile disposable lancet  Stopwatch  Plain capillary tubes  Procedure: 1. Disinfect the area of puncture with 70% alcohol. 2. Puncture to a depth of 3mm. 3. Start timer. 4. Fill up at least 2 plain capillary tubes. 5. Break off a portion of the tube every 30 seconds (approximately 1/4 of an inch) 6. Stop timer as soon as fibrin strands are seen bridging the 2 broken ends of the tube. 7. Normal value:  Dale and Laidlaw's method = 2-4 minutes  Sabraze's method = 3-7 minutes

Sheen. MT1144. HEMA LAB

C) WHOLE BLOOD CLOTTING TIME (LEE-WHITE)  Principle:  The whole blood clotting time is a rough measure of all intrinsic clotting factors in the absence of tissue factors. Variations are wide and the test sensitivity is limited. Whole blood, when removed from the vascular system and exposed to a foreign surface, will form a solid clot. Within limits, the time required for the formation of the solid clot is measure of the coagulation system.  Materials:  Stop watch equipment for collection of blood  2 plastic syringes  3 clean, dry glass test tubes  Water/ dry bath (at 37 degrees C)  70% alcohol  Sterile gauze  Procedure: 1. Label glass tube numbers one, two and three. 2. Collect at least 1-2 mL of blood in a plastic syringe. Discard this blood. (This prevents tissue thromboplastin from entering the blood sample). Change syringes. 3. Collect at least 5 mL of blood in the 2nd plastic syringe. 4. Approximately 1 mL of blood is placed in each of the three glass test tubes. (Number 3 first, then number 2, then number 1). 5. The stopwatch is started as soon as the blood enters the first tube number 3. 6. All tubes are placed into the 37 degrees C water bath. 7. Gently tilt tube number 3 (45 angle) every 30 seconds, until the blood in it clots. 8. Thirty seconds after tube number 3 clots, proceed with tube number 2, tilting every seconds, until a clot is formed. 9. Thirty seconds after tube number 2 is clotted, tube number 1 is tilted until no flow of blood is observed on tilting. 10. Record the time. The coagulation time is the time required for the blood to clot in the last tube. (Tube number 1) 11. Normal value 7-15 minutes.

Sheen. MT1144. HEMA LAB...