Blood collection
Islamic University – Gaza (IUG)
Introduction
Hematology: Is defined as the study of
blood.
Everybody is familiar with the sight of blood the red fluid that oozes out of your body when
you've sustained a cut or a deep injury, which is
slightly denser and approximately 3-4 times
more viscous than water.
Blood Volume:Blood volume is variable, but tend to be about 5- 6
liters , or 7- 8 % of the body weight. Factors such as body
size, amount of adipose tissue, and electrolyte concentrations
all affect volume.
Blood Composition:Approximately 45% of the blood is composed of formed
elements: red blood cells , white blood cells , and platelets.
The remaining 55% of the blood is fluid portion, of which
approximately 90% is water and 10% is composed of
proteins, carbohydrates, vitamins, hormones, enzymes, lipids,
and salts
Note:The components of blood can be separated by
filtration, however, the most common method of
separating blood is to centrifuge (spin) it.
Three layers are visible in centrifuged blood. The
straw-colored liquid portion, called plasma, forms at
the top (~55%). A thin cream-colored layer, called
the Buffy coat, forms below the plasma.
The Buffy coat consists of white blood cells and
platelets. The red blood cells form the heavy bottom
portion of the separated mixture (~45%).
Venipuncture (Phlebotomy)
• The process of obtaining intravenous
access.
• There are three veins most commonly used in venipuncture, or
phlebotomy:
 The cephalic
 The median cubital
 The basilic veins
• These three veins are found in the antecubital area.
• The cephalic vein is found on the lateral, or outside, of the arm.
• The median cubital vein, the preferred one to use, is found close to
the center.
• The basilic vein is located on the inner, or medial part of the
antecubital area.
Common Sites for Venipuncture
The median cubital vein is the preferred vein for
phlebotomy because:
 It is usually larger than the other veins.
 Best anchored vein (More stationary(.
• Veins can move, or roll, which makes it more
difficult to perform phlebotomy. The median
cubital is typically well anchored, which makes it
less likely that the patient will feel pain during
phlebotomy, or bruise afterwards.
Median Cubital – First Choice
• This vein is located in the antecubital
fossa. (the area of the arm in front of the
elbow)
• Well anchored vein, usually large and
prominent.
• Very few problems. Offering the best
chance for a close to painless puncture, as
there are few nerve endings close to this
vein.
Cephalic Vein – Second Choice
• Cephalic vein which is located on the
lateral side of the arm.
• This vein is usually well anchored.
• The cephalic vein may lie close to the
surface.
Basilic Vein – Third Choice
• Located on the medial side of the arm.
• In many patients this vein may not be well
anchored and will roll, making it difficult to
access with the needle.
• Additionally, this area is often more
sensitive, thus a stick is slightly more
painful for the patient
• The cephalic and basilic veins are only used if
the medial cubital vein is not felt.
• The cephalic vein is the second choice usually,
since it is fairly well anchored. This is often the
only vein that can be felt in patients who are
obese.
• The basilic vein is kept as a last choice option. It
rolls more easily and runs directly over a nerve
and an artery, making it a more dangerous and
painful area to use.
Hand Veins
• At times, none of the veins of the antecubital fossa will
be felt or not be able to be used due to intravenous
placement or injury, hand veins may be used.
• Veins of the hand and wrist are usually close to the
surface, but they are prone to movement and rolling.
• Using these veins tends to be more painful for the
patient, since there are nerves running through the hand
as well.
• If using these veins, it is important to anchor the vein
with your hand, holding it in place, when you are drawing
the blood.
Venipuncture, why?
• Intravenous therapy
• Venous blood sample
• Parenteral nutrition
Anticoagulants
• Most hematology and coagulation procedures must be
performed on whole blood or plasma. There for, as soon
as the blood is withdrawn from the patient, it is mixed
with an anticoagulant to prevent coagulation. The three
most commonly used anticoagulants in the hematology
laboratory are discussed below:
1- EDTA:
• Is generally available as the sodium, dipotassium or
tripotassium salt of ethylene diamine tetra acetic acid. It
is used in concentration of 1.5(±.25).
• EDTA prevents coagulation by binding the calcium in
the blood (calcium is required for blood coagulation).
Excessive concentration of EDTA cause:
• Shrinkage of the red blood cells leading to decreased
hematocrit, increased MCHC, falsely low ESR.
• Degenerative changes in the white cells and the
platelets will swill and break up causing a falsely
increased in platelet counts.
2- Sodium citrate:
• Is used for coagulation studies in a concentration of 1
part 0.109M sodium citrate (tri sodium citrate
dehydrate) to9 part whole blood.
• Sodium citrate prevents coagulation by binding the
calcium of the blood in a soluble complex.
3- Heparin:
• May be used in concentration of 15 to 30 units/ml of
whole blood. its may cause clumping of platelets and
white cells.
• Coagulation is prevented by interaction with anti
thrombin III and subsequent inhibition of thrombin.
Equipments
(Instruments)
Blood Collection tubes
• glass or plastic tube
with a rubber stopper.
• It has a vacuum so
that blood will flow
into the tube.
• anticoagulants and/or
other chemical
additives.
Blood collection tubes
• Rubber stoppers of
blood collection tubes
are color coded.
• Each type of stopper
indicates a different
additive or a different
tube type.
Blood collection tubes: Safety
• The rubber stopper is
positioned inside the
plastic shield
Syringes
Needles
Needles
• Different sizes.
• size =gauge.
• The larger the needle, the smaller the
gauge number.
• 21 or 22 gauge needle is mostly used.
Needle Components
Single Draw Needle
• Single draw needles
are of the type that fit
on a syringe, and can
be used only to fill the
syringe to which they
are connected.
Butterfly Needle
• Winged infusion set
• Difficult venipunctures
including pediatric
draws
• with a syringe or a
holder and vacuum
collection tube
system.
• 21, 23, or 25 gauge.
Lancets
• Lancets are used for
difficult
venipunctures,
including pediatric
draws.
Tourniquets
• Vein easier to SEE, FEEL and PUNCTURE
Sterilization
Bandaging Material
Gloves
• Gloves must be worn
for all procedures
requiring vascular
access.
• Non-powdered latex
gloves are most
commonly used;
Sharp Disposal Container
Collecting Blood
Greeting
• Always greet patient in a professional,
friendly manner.
• A good initial impression will earn the
patients trust, and make it easier and more
pleasant to draw a good specimen.
• Identify yourself by name and department.
• Explain the reason for your presence.
Technical Tip
• The more relaxed and trusting your
patient, the greater chance of a successful
non traumatic venipuncture.
• Good verbal, listening, and nonverbal
skills are very important for patient
reassurance
Patient Identification
• Make sure the name, medical record number, and date
of birth on your order/requisition match those on the
patient’s armband.
• Verify the patient’s identity by politely asking them to
state their full name.
• Properly identifying patients and specimens is probably
the single most critical part of your job.
• The consequences of misidentifying a specimen can be
life threatening.
• Never rely on the patient name on the door or above the
bed. Patients are frequently moved from room to room.
Technical Tip
• A hospitalized patient must always be
correctly identified by an ID band that is
attached to the patient.
Standard Precautions
Wash hands
Apply gloves
Technical Tip
• Patients are often reassured that proper
safety measures are being followed when
gloves are put on in their presence.
Position the Patient
• Comfortable position
• Turn the arm so that the wrist and palm
face upward, and the antecubital area is
accessible
Technical Tip
• When supporting the patient’s arm, do not
hyperextend the elbow. This may make
vein palpation difficult.
Applying the tourniquet
• Tie the tourniquet just above the elbow.
• The tourniquet should be applied a
maximum of 1 – 2 minutes.
Applying the tourniquet
Applying the tourniquet
• After applying the
tourniquet, you may
ask the patient to
make a fist to further
distend the arm veins.
Technical Tip
• Patients often think they are helping by
pumping their fists
• This is an acceptable practice when
donating blood, but not in sample
collection as this can lead to
hemoconcentration
Choose a site
• The median cubital vein
• If not accessible: Cephalic vein, or the
Basilic vein.
• If not accessible: veins on the back of the
hand.
• Use a much smaller needle for these hand
veins.
Never draw from these areas
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Scarred, abraded, or inflamed skin
Arms containing IV catheters
Edematous arms
Occluded Veins
Shunts
Cleansing the site
• Isopropyl alcohol swab
• Outward expanding spiral starting with the
actual venipuncture site.
• Allow the alcohol to dry:• 1-disinfect the site
• 2-prevent a burning sensation
Technical Tip
• Patients are quick to complain about a
painful venipuncture. The stinging
sensation caused by undry alcohol is a
frequent, yet easily avoided, cause of
complaints.
Hold vein in place
Insert needle
the needle bevel up
Push tube into holder
• Gently push the tube
onto the needle
holder so that the
catheter inside the
needle holder
penetrates the tube.
• Blood flow should be
visible at this point.
Technical Tip
• Allow tubes to fill until the vacuum is
exhausted to ensure the correct blood to
anticoagulant ratio.
Removing the Needle
• Gently release the tourniquet before the
last tube of blood is filled
• Remove the last tube from the needle
• Withdraw the needle in a single quick
movement
Apply Pressure
• Quickly place clean gauze over the site,
and apply pressure.
• You may ask the patient to continue
applying pressure until bleeding stops.
Apply Adhesive bandage
Technical Tip
• The practice of quickly applying tape over
the gauze without checking the puncture
site frequently produces a hematoma
Needle disposal
• Remove the needle from the holder if
appropriate, and properly discard it in an
approved sharps disposal container.
• Discard all waste and gloves in the
appropriate biohazardous waste container.
• Wash hands.
Specimen Labeling
• Label specimens at the bedside according
to your institution’s standard procedures,
or apply preprinted labels.
• Proper labeling is the single most critical
task you are asked to perform.
Proper labeling generally
includes:
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Patient’s first and last name
Hospital identification number
Date & time
Phlebotomist initials
Your institution may provide bar coded
computer generated labels that contain
this information.
REVIEW OF VENIPUNCTURE
PROCEDURE
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Patient identification
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Filling out the requisition
Equipment
Apply tourniquet and palpate for vein
Sterilize the site
Insert needle
Drawing the specimen
Releasing the tourniquet
Applying pressure over the vein
Applying bandage
Disposing needle into sharps
labeling the specimens
Perform Venipuncture
TROUBLESHOOTING
Blood won’t flow
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•
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If you do not see blood flow, the tip of the
needle:
May not yet be within the vein.
May have already passed through the
vein.
May have missed the vein entirely.
May be pushed up against the inside wall
of the vein.
Incomplete collection or no
blood is obtained:
• Change the position of the needle. Move it
forward (it may not be in the lumen)
• or move it backward (it may have
penetrated too far).
• Adjust the angle (the bevel may be against
the vein wall).
• Try another tube. There may be no
vacuum in the one being used.
• Re-anchor the vein. Veins sometimes roll
away from the point of the needle and
puncture site.
Other Problems
• A hematoma forms under the skin
adjacent to the puncture site - release the
tourniquet immediately and withdraw the
needle. Apply firm pressure.
• The blood is bright red (arterial) rather
than venous. Apply firm pressure for more
than 5 minutes
Capillary Puncture
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Safe
Quick
Small amount of blood
Increased use
Capillary Puncture Sites
• Fingertip
• Great toe
• Heel
Fingertip •
Great toe •
Heel •
Lancets
• Sterile
• Single-use
• Different lengths
Finger stick-Specimen collection
• A safety Lancet,
which controls the
depth of incision
Finger stick
• If possible, use the fourth (ring)
finger or the middle finger.
• Many patients prefer that you
use fingers on their
nondominant hand.
• Choose a puncture site near
the right or left edge of the
finger tip.
• Clean the site as you would for
routine venipuncture.
Finger stick
• Select a safety lancet
appropriate for the size of the
patient’s finger.
• You may warm the finger prior
to puncture to increase blood
flow.
• Make the puncture
perpendicular, rather than
parallel, to the finger print.
Finger stick
• Wipe away the first
drop of blood using
gauze to remove
tissue fluid
contamination.
Finger stick
• Collect blood into an
appropriate tube.
• Label specimens
appropriately.
• Make sure bleeding
has stopped. Apply
an adhesive bandage
if necessary.
• Discard sharps
appropriately.
• Peform finger or
heel puncture
across the
fingerprints as the
blood will more
likely bead rather
than run down the
"channels" of the
fingerprints.
Heel stick
• Veins of small
children and infants
are too small for
venipuncture;
• Butterfly needles may
be used to collect
venous blood in older
children.
Heel stick
• Firmly grasp the infants foot.
• Do not use a tourniquet.
• The heel may be warmed with
a cloth to help increase blood
flow.
• Wipe the collection site with an
alcohol prep pad, and allow
the alcohol to dry.
• Wipe the site with sterile cotton
or gauze, to be sure all the
alcohol has been removed.
Heel stick
• Puncture the left or
right side of the heel,
not the bottom of the
foot.
• Wipe away the first
drop of blood since it
may contain excess
tissue fluid or alcohol
which could alter test
results.
Heel stick
• Collect the blood into
the appropriate tube.
Heel stick
• After collection is
completed, apply
pressure to the
puncture site with a
sterile gauze pad until
bleeding has stopped.
• Do not apply an
adhesive bandage to
an infant’s foot since
it may injure its
delicate skin.
Heel stick
Fainting
• Rarely, patients will faint during
venipuncture.
• It is therefore important that patients are
properly seated or lying in such a way
during venipuncture so that if they do faint,
they won’t hurt themselves.
• self-limited
Fainting; what to do?
• Gently remove the tourniquet and needle
from the patients arm, apply gauze and
pressure to the skin puncture site.
• Call for help.
• If the patient is seated, place him on his
back, with his hips flexed to help blood
return to the brain.
• A cold compress on the back of the neck
may help to revive the patient more
quickly.