2. BLEEDING 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.
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3. PRINCIPLE
• A standardised incision is made on the volar
surface of the forearm
• The time the incision bleeds is measured
• Cessation of bleeding indicate the formation
of haemostatic plug
• Depends on the adequate no: of platelets and
on the ability of the platelets to adhere to the
subendothelium.
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7. PROCEDURE
• Clean the inner aspect of the fore arm
• Place a BP cuff on the upper arm , inflate to 40
mm of mercury.
• Select an area on the volar surface which is
devoid of veins
• Should be performed at room temperature.
• A disposable lancet with a point of about
3mm /No.11 bard parker surgical blade is
taken.
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8. • Three skin punctures 1mm deep and 3 mm long
are made.
• Stopwatch is started as soon as the bleeding
starts in each wound.
• Using the edge of a filter paper (whattman No:1) ,
blot the blood accumalated over the wound
• The time from which incision was made to the
time at which the bleeding stops to stain the filter
paper is taken.
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9. • The average of the 3 bleeding time is taken .
• The BP cuff is removed.
• The puncture wounds are cleaned
• Sterile bandage applied
• The longer of the duplicate bleeding time will
be the most accurate one.
• Longer bleeding time-puncture of superficial
veins
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10. • If bleeding continues more than 15 min-
apply pressure Repeat the bleeding time on
other arm.
• Report-greater than 15 min.
• Reports correlated with platelet count and
finger prick smear.
• Reference range-2-7’
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12. LIMITATIONS
• Not a very reliable test.
• The puncture wound may close before the
cessation of bleeding.
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13. STANDARD TEMPLATE METHOD
• More standardised method
• Uses a glass or plastic template
• Allows the lancet to make a cut-11 mm long
and 1mm deep.
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19. ADVANTAGES
• Test is very sensitive and reproducible
• Detects even minor alterations in platelet
function.
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20. DUKE’S METHOD
• Easy to perform
• Requires minimal equipment
• Requirements-alcohol,sterile
lancet,stopwatch,filter paper
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21. PROCEDURE
• Clean the ear lobe with alcohol sponge
• Infants-heel of foot
• Hold a glass slide behind the ear lobe
• Make a deep puncture with sterile lancet.
• Start the stop watch
• Discard the glass slide
• Using filter paper blot the drop of blood
coming out from incision.
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22. • When bleeding ceases stop the stop watch.
• Count the number of drop on the filterpaper
• Multiply by 30 sec
• Report the closest minute
• If the cut bleeds more than 10 ‘,discontinue
the test
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23. ADVANTAGES
• The ear lobule contain abundant
subcutaneous tissue and is vascular.
• Flow of the blood is quite good
• Normal bleeding time-3-5’
• DISADVANTAGE
• Difficult to get a standardised wound
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24. COPLEY AND LALITCH METHOD
• Clean the finger
• Make a puncture wound 6mm deep
• Immerse the wound in sterile physiological
saline warmed to 37o
• Laeve it until there is no free flow of blood
• The BT measured from the moment of the
wound to the cessation of bleeding.
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25. VARIABLES AFFECTING BT
• Anemia prolongs the bleeding time.
• Patients with thrombocytopenia(<100×109 /L)
Will have increased BT.
• Aspirin,pencillin,cephalothin prolongs BT
• Pediatric pts and neonates –smaller incisions
are required.pressure -20 mm of Hg.
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26. CLINICAL SIGNIFICANCE
• Prolonged BT in
Thromboctytopenia
Disorders in platelet fn-thrombasthenia,storage
pool disease,Bernard –Soulier syndrome
Afibrinogenemia
Severe hypofibrinogenemia
Vascular disorders
Aspirin
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27. Aplastic anaemia
A/c leukkemia
Liver diseases
Von Willibrand disease
DIC
Vascular abnormalities -Ehlers danlos
syndrome
Severe deficiency of factor V or XI
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28. 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.
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30. VENEPUNCTURE METHOD
• Sample collection
• 2 SYRINGE TECHNIQUE-avoid interference
from tissue fluid
• Draw 1 ml of blood into first syringe
• Without disturbing the position of the needle
2 nd syringe attached.
• 5ml of blood drawn
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31. EQUIPMENTS
• Cotton wool,surgical gauze soaked in
alcohol,plastic syringe
• Test tube-acid washed(10ml)
• Water bath -370 c.
• Stop watch
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32. PROCEDURE
• 2ml of venous blood collected quickly
• Start the stop watch as soon as the blood enters
the syringe
• Fill each of the tube to 1 ml mark.
• Plug the tube and place them in water bath at 370
c.
• After 5’ tilt the first tube at an angle 450 c.(room
temp-10’)
• If not clotted return to water bath
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33. • Examine at an interval of 30 sec
• When the blood is clotted it can be tilted at an
angle of 900 c without spilling the contents.
• As soon as blood is clotted,immediately
examine the second tube.
• Stop the stop watch and note the time.
• Coagulation time is the clotting time of the
second tube.
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35. • ADVANTAGE
• More accurate and standard method
• Test can be run with control
• DISADVANTAGE
• Only a rough method
• There can be contamination of syringe /tubes
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36. NORMAL VALUE
• DEPENDS ON THE METHOD USED
• Normal value-8-15’
• If 10 min inc done-20 -22 min
• Value<8min-contamination with tissue fluid
/hypercoagulability.
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37. SOURCES OF ERRORS
• Faulty technique
• Inappropriate volume of blood
• Faulty venepuncture
• Air bubble entering the syringe
• Diameter of the glass tube should be uniform
• Always use clean glass wares and plastic
syringe
• Vigorous agitation should be avoided.
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38. CAPILLARY METHOD
• PRINCIPLE-puncture the skin,blood is taken to
a plain capillary tube and stop watch started.
• Formation of fibrin strings is noted by
breaking the capillary tube at regular intervals.
• The time taken for the first appearance of the
fibrin string is noted.
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40. PROCEDURE
• Warm up the finger for skin puncture
• Make an incision with a sterile disposable
lancet to depth of 3mm.
• As soon as blood is visible- start the stop
watch.
• Wipe off the first drop of blood
• Allow 2nd drop of blood to flow to capillary
tube .
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41. • After 2’ break off the capillary tubing,1-2 cm
from the end.
• When a thin string of fibrin can be seen in
between the broken end of the capillary
tube,stop the watch and note the time
• Report the time
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42. • DISADVANTAGE
• This method is insensitive
• This method is unreliable
• Capillary blood always contaminated with tissue
fluid
• ADVANTAGE
• Can be performed when venous blood cannot be
obtained
• NORMAL CT-1-5 min.
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44. HEPARIN RETARDED BLOOD
COAGULATION TIME
• REQUIREMENTS
• .004 mg per ml of isotonic saline.
• Venous blood freshly drawn in to syringe
• TECHNIQUE
• Add 1ml of heparin solution in a clean dry test tube in
waterbath at 370 c
• Add 1ml of blood to this test tube and invert twice.
• A t the end of 12 min,tilt the tube gently at I min
interval.
• Look for clot formation
• Normal range-20-35 min
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45. SIGNIFICANCE
• It appears to be the most valuable single test
of coagulation.
• Test used to detect hypercoagulable and
hypocoagulable states.
• Prolonged clotting time seen in deficiency
states involving AHG,Plasma thromoblastin
component, plasma thromboplastin activator.
• Also prolonged in pt with bone marrow
depression and thrombocytopenia.
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46. ACTIVATED CLOTTING TIME
• Used to access heparin effects during cardiac
surgery
• Negatively charged clotting cascade activators are
used-celite,kaolin.
• Look for clot formation-either
optical/electromagnetic method
• Normal value-celite -100-170 sec
• Kaolin-90-150 sec
• ACT MONITORS-HEMOCHRON ACT,HEMOTECH
AUTOMATED ANTICOAGULATION TIMER.
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47. CLINICAL SIGNIFICANCE
• Only severe clotting factor deficiency can be
recognised
• 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
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Editor's Notes
Arm should be supine on a firm support ,preferably closee to the level of heart.,site-lateral 1/3rd of the forearm 2-3 cm below the anticubital crease.A locatioin on the median aspect of the calf abt 6-8 cm below the knee can also be taken.
Either parallel or perpendicular to the anticubital crease.
Care should be taken not to touch the developing platelet plug.Rounded to the nearest 30 sec is taken as the BT.
Than taking theb average of the 2 .
Stop the bleeding.Criitical values which needs urgent clinical notification are values above 15’.
It is a standardised spring loaded razor device that produces a deftinite incision.eg 1mm deep 3mm long incision.
Do not rub.allow to dry completely.
Apply pressure on the bleeding spot.
/
b/c of the ease of doing.Not affected by the deficiecy of plts since not very many plts are required to get a normal result in this test.Small amt of thrombin isb required so mild to modereate defiency of plasma factor will be missed.
Which rinse out the tissue fliud as it has passed thru the needle.
Remove the needle.room temp-cold prolongs-hot weather hastens
Tilting can promote clotting .so too much tilting is avioded.hwnce difficult to detect hypercoagulable states.The purpose of first tube is when to start look at the 2nd tube.
Syringe-tissue fliud.tube-ca
Vol less than 1ml –give shorter time.CT accelarated by narrow tube