Bleeding time
Screening test for detecting disorders of
functional platelet and for Von
Willebrand disease, and is directly
affected by platelet count and the ability
of platelets to form a platelet plug
Prolonged in thrombocytopenia, Von
Willebrand disease, and following
ingestion of aspirin, aspirin-containing
compounds, anti-inflammatory drugs,
anticoagulants, some antibiotics and
certain other drugs.
Methods
01
Duke method
02
Ivy method
03
Template method
DUKE METHOD
Site:
earlobe/
fingertip
Device:
feather
lancet
Incision size:
lancet – size
dependent
Normal
value: 1-3
minutes
DUKE METHOD
1. Cleanse the ear lobe of the patient with alcohol and
air dry.
2. Puncture the ear lobe with the right hand while the left
hand is holding the glass slide.
3. Turn on the stopwatch.
4. Hold the filter paper under the ear and let blood drop
from the ear lobe to the filter. Do not apply pressure to
the ear.
5. When blood no longer drops from the ear, turn the
stopwatch off and record the time. The length of time
from the puncture until the blood no longer flows is the
bleeding time.
IVY METHOD
Site: volar
surface of the
forearm
approximately
5 cm below
the
antecubital
crease
Device:
feather
lancet with
blood
pressure cuff
inflated to
40 mmHg
Incision size:
parallel to
antecubital,
3-5 mm
(depends on
the size of
the lancet)
Normal
value:
2.5 – 7
minutes
IVY METHOD
1. Place a blood pressure cuff around the arm above the elbow and
inflate to 40mmHg. Maintain this pressure throughout the procedure.
2. Clean the skin of the fleshy portion of the forearm below the
antecubital fossa with alcohol and allow to airdry.
3. Tense the skin and proposed test site by gasping the posterior
portion of the arm between the thumb and forefinger of the left
hand.
4. Pierce the stretched skin with disposable lancet all the way down;
turn the stopwatch on.
5. Absorb the drops of blood at 30-second interval on the filter paper
until the blood ceases. Turn off the stopwatch and record time.
6. Label the center of the filter paper with name, date and bleeding
time.
TEMPLATE
METHOD
Site: volar
surface of the
forearm
approximately
5 cm below
the
antecubital
crease
Device:
disposable
template
device with
blood pressure
cuff inflated
to 40 mmHg
Incision size:
Adult (white) –
5.0 mm long, 1
mm deep
Pediatrics
(pink) – 3.5 mm
long, 1 mm
deep
Normal
value:
2-8
minutes
Simplate
Contains a springloaded blade
within a plastic
case
Guillotine-like cut
in the skin
Surgicutt
Utilizes a slicing
action using a
surgical blade
Spring loaded;
blade automatically
retracts into the
housing after it has
made a
standardized cut
TEMPLATE METHOD
1. Place the patient’s arm on a steady support with the volar surface exposed.
Lightly shave the area if body hair will interfere with the test.
2. Place the sphygmomanometer cuff on the upper arm. Inflate the cuff to
40mmHg.
For newborns: Venostasis pressure should be maintained in accordance with the
weight of the newborn. The following pressures are recommended for use in
conjunction with the newborn weight:
*The time between inflation of cuff
20 mmHg for infants - 1,000g or less
and incision should be 30-60 seconds.
25 mmHg for infants - 1,000g - 2000g
Hold at this exact pressure for the
30 mmHg for infants - 2,000g or greater duration of the test.
3.Cleanse the area with an antiseptic swab and allow to air dry.
4. Remove the template device from the blister pack, being careful not to
contaminate or touch the blade-slot surface.
5. Remove the safety clip. Once removed, do not push the trigger.
6. Hold the device securely between the thumb and the middle finger.
7.Gently rest the device on the patient’s forearm and apply minimal pressure on the
skin.
TEMPLATE METHOD
8.Gently push the trigger, starting the stopwatch simultaneously.
9. Remove the device from the patient’s forearm immediately after
triggering.
10. Every 30 seconds, wick the blood with blotting paper. Bring the
blotting 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. Wick the blood every 30 seconds until blood no longer stains the
paper. Stop the timer. Bleeding time is determined to the nearest 30
seconds.
12. Remove the sphymomanometer cuff and cleanse the incision site
with an antiseptic swab. Potential scarring can be reduced by
approximating the skin edges with a non-allergenic wound closure
strip for 24 hours.
Bleeding time devices
Device
No. of Incisions
Length/Depth of
Incision (mm)
Simplate Pediatric
1
3.0 x 0.5
Perpendicular/Parallel
Simplate
1
5.0 x 1.0
Parallel
Simplate II
2
5.0 x 1.0
Parallel
Surgicutt
1
5.0 x 1.0
Parallel
Surgicutt 2
2
5.0 x 1.0
Parallel
Surgicutt Newborn
1
2.5 x 0.5
Perpendicular
Surgicutt Jr.
1
3.5 x 1.0
Parallel
Position of Choice
EQUIPMENT
Blood pressure cuff
Bleeding time device
Stopwatch
Wattman filter paper
Alcohol prep pads
Bandage
PRINCIPLE
A blood pressure cuff is placed on
the patient’s arm above the elbow,
inflated, and maintained at a
constant pressure throughout the
procedure. One or two
standardized incisions are made
on the volar surface of the
forearm. The length of time
required for bleeding to stop is
recorded as the bleeding time.
PROCEDURE
1.) Locate the area for the bleeding time.
PROCEDURE
1.) Locate the area for the bleeding time.
PROCEDURE
2) Cleanse the site with an alcohol and
allow to dry.
3) Place a blood pressure cuff on the
patient’s arm above the elbow. Increase
the pressure to 40 mmHg (or lower for
newborns) and hold this exact pressure
for the entire procedure.
PROCEDURE
4) Prepare the bleeding time device. Position it
in the correct direction and appropriate area on
the arm, using only that amount of downward
pressure so that both ends are touching the skin
and the device does not cause an indentation.
5) Activate the trigger and start the stop watch.
Remove the device approximately 1 second after
making the incision.
PROCEDURE
6) Blot the blood from the puncture site on a
clean section of circular filter paper every 30
seconds.
7) When the bleeding ceases, stop the watch and
release the blood pressure cuff. Record the
results.
8) Place a bandage over the puncture site.
DISCUSSION
The aspirin tolerance test
may be useful in helping to
distinguish functionally
abnormal platelets from
normal platelets
When performing a
bleeding time on infants,
use Surgicutt Newborn
The incision must be made
consistently in the same
direction
Clotting
time
Generally measures intrinsic and common
pathways and monitor heparin therapy
Time it takes for blood to solidify after it has
been out of the vessel and upon activation of
the coagulation factors
Methods
01
Slide Method
02
Capillary Tube Method
03
Lee and White Method
Slide method
Also called as drop method
Site: fingertip
Materials used: pricker, clean glass slide
Puncture to a depth of 3mm
Normal value: 2-4 minutes
Capillary tube method
Sabraze’s Method, Dale and Laidlaw’s Method
Site: fingertip
Materials used: pricker, plain glass capilet
Puncture to a depth of 3mm
Normal value:
Sabraze’s Method: 3-7 minutes
Dale and Laidlaw’s Method: 2-4 minutes
Lee and White method
Routinely used
Perform venipuncture to obtain blood sample
Material used: syringe
Main stimulus: clean glass test tubes
Normal value: 5-15 minutes
Specimen: Freshly drawn venous blood
Lee and White method
PRINCIPLE
The time required for the clot to form is a measure of the overall
intrinsic and common pathway
Freshest volume of blood sample is the 1ˢᵗ volume of blood wherein
coagulation factors are activated whereas the 1ˢᵗ volume of blood
taken out from the blood vessel is the last volume of blood wherein
the coagulation factors are activated
PROCEDURE
1. Label 3 test tubes (#1, #2, #3) and premoisten with NSS.
2. Perform venipuncture and withdraw 3 ml
of venous blood.
3. Start the timer as soon as blood enters the
hub of the needle.
4. Carefully transfer 1 ml of blood to each of
the 3 tubes and incubate in waterbath.
5. Tilt test tube 1 every 30 seconds until blood
clots and record time.
6. Do the same with the 2ⁿᵈ tube until blood
clots and also do the same with the 3ʳᵈ
tube.
7. Report the time required for the blood in
the 3ʳᵈ tube to clot as the clotting time.
CENTRIFUGATION
Centrifuge uses centrifugal force to
separate phases of suspensions by
different densities
Frequently used in processing blood
to derive plasma or serum fractions
Urine and body fluids may be
centrifuged to concentrate
particulate matter as sediment to be
examined
Conditions should specify both the
time and the centrifugal force
Centrifuge selection
Must have the highest
possible centrifugal force
and not rotational speed
RCF in g units
Multiples of the
gravitational force
Key points to remember
Tubes, carriers, or shields of equal weight, shape, and
size should be placed in opposing positions in the
centrifuge head to achieve appropriate balance
Tubes must be balanced across the center of rotation,
and each bucket must be balanced with respect to its
pivotal axis
Specimens must be placed with regard for a
geometrically symmetrical arrangement, using waterfilled tubes to attain balance
EQUIPMENT
1. Tabletop, general laboratory
centrifuges
2. Horizontal head, fixed angle, or
angle-head
3. High speed centrifuges
4. Portable
floor
models,
undercounter models
5. Microcentrifuges
6. Refrigerated and unrefrigerated
types
7. Ultracentrifuge models
Aliquot preparation
Often created when multiple tests are
ordered on a single specimen
Prepared by transferring a portion of the
specimen into one or more tubes labeled with
the same id information as the specimen tube
Once transferred into an aliquot tube, serum
and plasma are virtually indistinguishable
Serum and plasma or plasma obtained from
different types of anticoagulant must not be
mixed together
If testing is to be delayed, most samples can
be refrigerated at 4°C for up to 8 hours