BLEEDING TIME
AND
CLOTTING TIME
SUNIL KUMAR.P
Dept. of Haematology
SJMCH, Bangalore
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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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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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METHODS
• Standard template method
• Dukes method
• Ivy’s method
• Copley and lalitch method
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IVY’S METHOD
REQUIREMENTS:
BP cuff
Disposable lancet
Stop watch
Filter paper
Spirit/alcohol
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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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• 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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• 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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• If bleeding continues more than 15 minapply 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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ADVANTAGE
• Standardised method
• Bleeding time more accurate
• Normal BT-3-8’.
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LIMITATIONS
• Not a very reliable test.
• The puncture wound may close before the
cessation of bleeding.
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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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PROCEDURE
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ADVANTAGES
• Test is very sensitive and reproducible
• Detects even minor alterations in platelet
function.
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DUKE’S METHOD
• Easy to perform
• Requires minimal equipment
• Requirements-alcohol,sterile
lancet,stopwatch,filter paper
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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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• 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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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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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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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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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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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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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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METHODS
• Venepuncture method-Modified lee and white
method
• Capillary method
• Heparin retarded blood coagulation time
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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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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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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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• 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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• 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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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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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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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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EQUIPMENT
• Disposable lancet
• Capillary tubing10-15 cm length and 1.5 mm
diameter without anticoagulant
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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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• 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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• 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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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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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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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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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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