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Phlebotomy
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BLOOD COLLECTION:
ROUTINE
VENIPUNCTURE AND SPECIMEN HANDLING
Objectives for the tutorial:
- Describe and perform the
venipuncture process including:
- Proper patient
identification procedures.
- Proper equipment selection
and use.
- Proper labelling procedures
and completion of laboratory requisitions.
- Order of draw for multiple
tube phlebotomy.
- Preferred venous access
sites, and factors to consider in site
selection, and ability to differentiate
between the feel of a vein, tendon and artery.
- Patient care following
completion of venipuncture.
- Safety and infection
control procedures.
- Quality assurance issues.
- Identify the additive,
additive function, volume, and specimen
considerations to be followed for each of the
various color coded tubes.
- List six areas to be avoided
when performing venipuncture and the reasons for
the restrictions.
- Summarize the problems that
may be encountered in accessing a vein,
including the procedure to follow when a
specimen is not obtained.
- List several effects of
exercise, posture, and tourniquet application
upon laboratory values.
VENIPUNCTURE PROCEDURE
- The venipuncture procedure is
complex, requiring both knowledge and skill to
perform. Each phlebotomist generally establishes
a routine that is comfortable for her or him.
Several essential steps are required for every
successful collection procedure:
- Identify the patient.
- Assess the patient's
physical disposition (i.e. diet, exercise,
stress, basal state).
- Check the requisition form
for requested tests, patient information, and
any special requirements.
- Select a suitable site for
venipuncture.
- Prepare the equipment, the
patient and the puncture site.
- Perform the venipuncture.
- Collect the sample in the
appropriate container.
- Recognize complications
associated with the phlebotomy procedure.
- Assess the need for sample
recollection and/or rejection.
- Label the collection tubes
at the bedside or drawing area.
- Promptly send the specimens
with the requisition to the laboratory.
ORDER FORM / REQUISITION
- A requisition form must
accompany each sample submitted to the
laboratory. This requisition form must contain
the proper information in order to process the
specimen. The essential elements of the
requisition form are:
- Patient's surname, first
name, and middle initial.
- Patient's ID number.
- Patient's date of birth and
sex.
- Requesting physician's
complete name.
- Source of specimen. This
information must be given when requesting
microbiology, cytology, fluid analysis, or other
testing where analysis and reporting is site
specific.
- Date and time of collection.
- Initials of phlebotomist.
- Indicating the test(s)
requested.
- An example of a simple
requisition form with the essential elements is
shown below:
LABELING THE SAMPLE
- A properly labelled sample
is essential so that the results of the test
match the patient. The key elements in
labelling are:
- Patient's surname, first
and middle.
- Patient's ID number.
- NOTE: Both of the above
MUST match the same on the requisition form.
- Date, time and initials
of the phlebotomist must be on the label of
EACH tube.
- An example of a simple
requisition form with the essential elements
is shown below:
EQUIPMENT:
- THE FOLLOWING ARE NEEDED
FOR ROUTINE VENIpuncture:
- Evacuated Collection Tubes
- The tubes are designed to fill with a
predetermined volume of blood by vacuum. The
rubber stoppers are color coded according to
the additive that the tube contains. Various
sizes are available. Blood should NEVER
be poured from one tube to another since the
tubes can have different additives or coatings
(see illustrations at end).
- Needles - The gauge number
indicates the bore size: the larger the gauge
number, the smaller the needle bore. Needles
are available for evacuated systems and for
use with a syringe, single draw or butterfly
system.
- Holder/Adapter - use with
the evacuated collection system.
- Tourniquet - Wipe off with
alcohol and replace frequently.
- Alcohol Wipes - 70%
isopropyl alcohol.
- Povidone-iodine wipes/swabs
- Used if blood culture is to be drawn.
- Gauze sponges - for
application on the site from which the needle
is withdrawn.
- Adhesive bandages / tape -
protects the venipuncture site after
collection.
- Needle disposal unit -
needles should NEVER be broken, bent, or
recapped. Needles should be placed in a proper
disposal unit IMMEDIATELY after their use.
- Gloves - can be made of
latex, rubber, vinyl, etc.; worn to protect
the patient and the phlebotomist.
- Syringes - may be used in
place of the evacuated collection tube for
special circumstances.
- ORDER OF DRAW:
- Blood collection tubes must
be drawn in a specific order to avoid
cross-contamination of additives between
tubes. The recommended order of draw is:
- First - blood culture tube
(yellow-black stopper)
- Second - non-additive tube
(red stopper or SST)
- Third - coagulation tube
(light blue stopper). A light blue stopper
(sodium citrate) tube is NEVER the first tube
drawn. If a coagulation assay is the only test
ordered, draw a non-additive tube (red stopper
or SST) first, and then draw the light blue
stopper tube.
- Last draw - additive tubes
in this order:
- Heparin (dark green
stopper)
- EDTA (lavender stopper)
- Oxalate/fluoride (light
gray stopper)
- NOTE:Tubes
with additives must be thoroughly mixed.
Erroneous test results may be obtained when
the blood is not thoroughly mixed with the
additive.
PROCEDURAL ISSUES
- PATIENT RELATIONS AND
IDENTIFICATION:
- The phlebotomist's role
requires a professional, courteous, and
understanding manner in all contacts with the
patient. Greet the patient and identify
yourself and indicate the procedure that will
take place. Effective communication - both
verbal and nonverbal - is essential.
- Proper patient
identification MANDATORY. If an inpatient is
able to respond, ask for a full name and
always check the armband for confirmation.
DO NOT DRAW BLOOD IF THE ARMBAND IS MISSING.
An outpatient must provide identification
other than the verbal statement of a name.
Using the requisition for reference, ask a
patient to provide additional information such
as a surname or birthdate.
- If possible, speak with the
patient during the process. The patient who is
at ease will be less focused on the procedure.
Always thank the patient and excuse yourself
courteously when finished.
- PATIENT'S BILL OF
RIGHTS:
- The Patient's Bill of
Rights has been adopted by many hospitals as
declared by the Joint Commission on
Accreditation of Healthcare Organizations
(JCAHO). The basic patient rights endorsed by
the JCAHO follow in condensed form are given
below.
- The patient has the right
to:
- Impartial access to
treatment or accommodations that are
available or medically indicated, regardless
of race, creed, sex, national origin, or
sources of payment for care.
- Considerate, respectful
care.
- Confidentiality of all
communications and other records pertaining
to the patient's care.
- Expect that any
discussion or consultation involving the
patient's case will be conducted discreetly
and that individuals not directly involved
in the case will not be present without
patient permission.
- Expect reasonable safety
congruent with the hospital practices and
environment.
- Know the identity and
professional status of individuals providing
service and to know which physician or other
practitioner is primarily responsible for
his or her care.
- Obtain from the
practitioner complete and current
information about diagnosis, treatment, and
any known prognosis, in terms the patient
can reasonably be expected to understand.
- Reasonable informed
participation in decisions involving the
patient's health care. The patient shall be
informed if the hospital proposes to engage
in or perform human experimentation or other
research/educational profits affecting his
or her care or treatment. The patient has
the right to refuse participation in such
activity.
- Consult a specialist at
the patient's own request and expense.
- Refuse treatment to the
extent permitted by law.
- Regardless of the source
of payment, request and receive an itemized
and detailed explanation of the total bill
for services rendered in the hospital.
- Be informed of the
hospital rules and regulations regarding
patient conduct.
- VENIpuncture SITE
SELECTION:
- Although the larger and
fuller median cubital and cephalic veins of
the arm are used most frequently, wrist and
hand veins are also acceptable for
venipuncture.
- Certain areas are to be
avoided when choosing a site:
- Extensive scars from
burns and surgery - it is difficult to
puncture the scar tissue and obtain a
specimen.
- The upper extremity on
the side of a previous mastectomy - test
results may be affected because of
lymphedema.
- Hematoma - may cause
erroneous test results. If another site is
not available, collect the specimen distal
to the hematoma.
- Intravenous therapy (IV)
/ blood transfusions - fluid may dilute the
specimen, so collect from the opposite arm
if possible. Otherwise, satisfactory samples
may be drawn below the IV by following these
procedures:
- Turn off the IV for at
least 2 minutes before venipuncture.
- Apply the tourniquet
below the IV site. Select a vein other
than the one with the IV.
- Perform the
venipuncture. Draw 5 ml of blood and
discard before drawing the specimen tubes
for testing.
- Cannula/fistula/heparin
lock - hospitals have special policies
regarding these devices. In general, blood
should not be drawn from an arm with a
fistula or cannula without consulting the
attending physician.
- Edematous extremities -
tissue fluid accumulation alters test
results.
- PROCEDURE FOR VEIN
SELECTION:
- Palpate and trace the
path of veins with the index finger.
Arteries pulsate, are most elastic, and have
a thick wall. Thrombosed veins lack
resilience, feel cord-like, and roll easily.
- If superficial veins are
not readily apparent, you can force blood
into the vein by massaging the arm from
wrist to elbow, tap the site with index and
second finger, apply a warm, damp washcloth
to the site for 5 minutes, or lower the
extremity over the bedside to allow the
veins to fill.
- PERFORMANCE OF A
VENIpuncture:
- Approach the patient in a
friendly, calm manner. Provide for their
comfort as much as possible, and gain the
patient's cooperation.
- Identify the patient
correctly.
- Properly fill out
appropriate requisition forms, indicating
the test(s) ordered.
- Verify the patient's
condition. Fasting, dietary restrictions,
medications, timing, and medical treatment
are all of concern and should be noted on
the lab requisition.
- Position the patient. The
patient should either sit in a chair, lie
down or sit up in bed. Hyperextend the
patient's arm.
- Apply the tourniquet 3-4
inches above the selected puncture site. Do
not place too tightly or leave on more than
2 minutes.
- The patient should make a
fist without pumping the hand.
- Select the venipuncture
site.
- Prepare the patient's arm
using an alcohol prep. Cleanse in a circular
fashion, beginning at the site and working
outward. Allow to air dry.
- Grasp the patient's arm
firmly using your thumb to draw the skin
taut and anchor the vein. The needle should
form a 15 to 30 degree angle with the
surface of the arm. Swiftly insert the
needle through the skin and into the lumen
of the vein. Avoid trauma and excessive
probing.
- When the last tube to be
drawn is filling, remove the tourniquet.
- Remove the needle from
the patient's arm using a swift backward
motion.
- Press down on the gauze
once the needle is out of the arm, applying
adequate pressure to avoid formation of a
hematoma.
- Dispose of contaminated
materials/supplies in designated containers.
- Mix and label all
appropriate tubes at the patient bedside.
- Deliver specimens
promptly to the laboratory.
- PERFORMANCE OF A
FINGERSTICK:
- Follow the procedure as
outlined above for greeting and identifying
the patient. As always, properly fill out
appropriate requisition forms, indicating
the test(s) ordered.
- Verify the patient's
condition. Fasting, dietary restrictions,
medications, timing, and medical treatment
are all of concern and should be noted on
the lab requisition.
- Position the patient. The
patient should either sit in a chair, lie
down or sit up in bed. Hyperextend the
patient's arm.
- The best locations for
fingersticks are the 3rd and 4th fingers of
the non-dominant hand. Do not use the tip of
the finger or the center of the finger.
Avoid the side of the finger where there is
less soft tissue, where vessels and nerves
are located, and where the bone is closer to
the surface. The 2nd (index) finger tends to
have thicker, callused skin. The fifth
finger tends to have less soft tissue
overlying the bone. Avoid puncturing a
finger that is cold or cyanotic, swollen,
scarred, or covered with a rash.
- Using a sterile lancet,
make a skin puncture just off the center of
the finger pad. The puncture should be made
perpendicular to the ridges of the
fingerprint so that the drop of blood does
not run down the ridges.
- Wipe away the first drop
of blood, which tends to contain excess
tissue fluid.
- Collect drops of blood
into the collection device by gently
massaging the finger. Avoid excessive
pressure that may squeeze tissue fluid into
the drop of blood.
- Cap, rotate and invert
the collection device to mix the blood
collected.
- Have the patient hold a
small gauze pad over the puncture site for a
couple of minutes to stop the bleeding.
- Dispose of contaminated
materials/supplies in designated containers.
- Label all appropriate
tubes at the patient bedside.
- Deliver specimens
promptly to the laboratory.
- ADDITIONAL
CONSIDERATIONS:
- To prevent a hematoma:
- Puncture only the
uppermost wall of the vein
- Remove the tourniquet
before removing the needle
- Use the major superficial
veins
- Make sure the needle
fully penetrates the upper most wall of the
vein. (Partial penetration may allow blood
to leak into the soft tissue surrounding the
vein by way of the needle bevel)
- Apply pressure to the
venipuncture site
- To prevent hemolysis
(which can interfere with many tests):
- Mix tubes with
anticoagulant additives gently 5-10 times
- Avoid drawing blood from
a hematoma
- Avoid drawing the plunger
back too forcefully, if using a needle and
syringe, and avoid frothing of the sample
- Make sure the
venipuncture site is dry
- Avoid a probing,
traumatic venipuncture
- Indwelling Lines or
Catheters:
- Potential source of test
error
- Most lines are flushed
with a solution of heparin to reduce the
risk of thrombosis
- Discard a sample at least
three times the volume of the line before a
specimen is obtained for analysis
- Hemoconcentration:
An increased concentration of larger molecules
and formed elements in the blood may be due to
several factors:
- Prolonged tourniquet
application (no more than 2 minutes)
- Massaging, squeezing, or
probing a site
- Long-term IV therapy
- Sclerosed or occluded
veins
- Prolonged Tourniquet
Application:
- Primary effect is
hemoconcentration of non-filterable elements
(i.e. proteins). The hydrostatic pressure
causes some water and filterable elements to
leave the extracellular space.
- Significant increases can
be found in total protein, aspartate
aminotransferase (AST), total lipids,
cholesterol, iron
- Affects packed cell
volume and other cellular elements
- Patient Preparation
Factors:
- Therapeutic Drug
Monitoring: different pharmacologic agents
have patterns of administration, body
distribution, metabolism, and elimination
that affect the drug concentration as
measured in the blood. Many drugs will have
"peak" and "trough" levels that vary
according to dosage levels and intervals.
Check for timing instructions for drawing
the appropriate samples.
- Effects of Exercise:
Muscular activity has both transient and
longer lasting effects. The creatine kinase
(CK), aspartate aminotransferase (AST),
lactate dehydrogenase (LDH), and platelet
count may increase.
- Stress: May cause
transient elevation in white blood cells (WBC's)
and elevated adrenal hormone values (cortisol
and catecholamines). Anxiety that results in
hyperventilation may cause acid-base
imbalances, and increased lactate.
- Diurnal Rhythms: Diurnal
rhythms are body fluid and analyte
fluctuations during the day. For example,
serum cortisol levels are highest in early
morning but are decreased in the afternoon.
Serum iron levels tend to drop during the
day. You must check the timing of these
variations for the desired collection point.
- Posture: Postural changes
(supine to sitting etc.) are known to vary
lab results of some analytes. Certain larger
molecules are not filterable into the
tissue, therefore they are more concentrated
in the blood. Enzymes, proteins, lipids,
iron, and calcium are significantly
increased with changes in position.
- Other Factors: Age,
gender, and pregnancy have an influence on
laboratory testing. Normal reference ranges
are often noted according to age.
SAFETY AND INFECTION CONTROL
- Because of contacts with
sick patients and their specimens, it is
important to follow safety and infection
control procedures.
- PROTECT YOURSELF
- Practice universal
precautions:
- Wear gloves and a lab
coat or gown when handling blood/body
fluids.
- Change gloves after
each patient or when contaminated.
- Wash hands frequently.
- Dispose of items in
appropriate containers.
- Dispose of needles
immediately upon removal from the patient's
vein. Do not bend, break, recap, or resheath
needles to avoid accidental needle puncture
or splashing of contents.
- Clean up any blood spills
with a disinfectant such as freshly made 10%
bleach.
- If you stick yourself
with a contaminated needle:
- Remove your gloves and
dispose of them properly.
- Squeeze puncture site
to promote bleeding.
- Wash the area well with
soap and water.
- Record the patient's
name and ID number.
- Follow institution's
guidelines regarding treatment and
follow-up.
- NOTE: The use of
prophylactic zidovudine following blood
exposure to HIV has shown effectiveness
(about 79%) in preventing seroconversion
- PROTECT THE PATIENT
- Place blood collection
equipment away from patients, especially
children and psychiatric patients.
- Practice hygiene for the
patient's protection. When wearing gloves,
change them between each patient and wash
your hands frequently. Always wear a clean
lab coat or gown.
TROUBLESHOOTING GUIDELINES:
- IF AN 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).
- Loosen the tourniquet. It
may be obstructing blood flow.
- 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.
- IF BLOOD STOPS FLOWING
INTO THE TUBE:
- The vein may have
collapsed; resecure the tourniquet to
increase venous filling. If this is not
successful, remove the needle, take care of
the puncture site, and redraw.
- The needle may have
pulled out of the vein when switching tubes.
Hold equipment firmly and place fingers
against patient's arm, using the flange for
leverage when withdrawing and inserting
tubes.
- PROBLEMS OTHER THAN AN
INCOMPLETE COLLECTION:
- 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.
BLOOD COLLECTION ON BABIES:
- The recommended location
for blood collection on a newborn baby or
infant is the heel. The diagram below
indicates in green the proper area to use for
heel punctures for blood collection:
- Prewarming the infant's
heel (42 C for 3 to 5 minutes) is important to
obtain capillary blood blood gas samples and
warming also greatly increases the flow of
blood for collection of other specimens.
However, do not use too high a temperature
warmer, because baby's skin is thin and
susceptible to thermal injury.
- Clean the site to be
punctured with an alcohol sponge. Dry the
cleaned area with a dry cotton sponge. Hold
the baby's foot firmly to avoid sudden
movement.
- Using a sterile blood
lancet, puncture the side of the heel in the
appropriate regions shown above in green. Do
not use the central portion of the heel
because you might injure the underlying bone,
which is close to the skin surface. Do not use
a previous puncture site. Make the cut across
the heelprint lines so that a drop of blood
can well up and not run down along the lines.
- Wipe away the first drop of
blood with a piece of clean, dry cotton. Since
newborns do not often bleed immediately, use
gentle pressure to produce a rounded drop of
blood. Do not use excessive pressure or heavy
massaging because the blood may become diluted
with tissue fluid.
- Fill the capillary tube(s)
or micro collection device(s) as needed.
- When finished, elevate the
heel, place a piece of clean, dry cotton on
the puncture site, and hold it in place until
the bleeding has stopped.
- Be sure to dispose of the
lancet in the appropriate sharps container.
Dispose of contaminated materials in
appropriate waste receptacles. Remove your
gloves and wash your hands.
COLLECTION TUBES FOR
PHLEBOTOMY
| Red Top |
|
| ADDITIVE |
None |
| MODE OF ACTION
|
Blood clots, and the
serum is separated by centrifugation
|
| USES |
Chemistries, Immunology
and Serology, Blood Bank (Crossmatch)
|
| Gold Top |
|
| ADDITIVE |
None |
| MODE OF ACTION
|
Serum separator tube
(SST) contains a gel at the bottom to
separate blood from serum on centrifugation
|
| USES |
Chemistries, Immunology
and Serology |
| Light Green Top
|
|
| ADDITIVE |
Plasma Separating Tube
(PST) with Lithium heparin |
| MODE OF ACTION
|
Anticoagulates with
lithium heparin; Plasma is separated with
PST gel at the bottom of the tube
|
| USES |
Chemistries |
| Red-Gray Top |
|
| ADDITIVE |
Serum Separating Tube
(SST) with clot activator |
| MODE OF ACTION
|
Forms clot quickly and
separates the serum with SST gel at the
bottom of the tube |
| USES |
Chemistries |
| Purple Top |
|
| ADDITIVE |
EDTA liquid |
| MODE OF ACTION
|
Forms calcium salts to
remove calcium |
| USES |
Hematology (CBC) and
Blood Bank (Crossmatch); requires full
draw - invert 8 times to prevent
clotting and platelet clumping |
| Light Blue Top
|
|
| ADDITIVE |
Sodium citrate
|
| MODE OF ACTION
|
Forms calcium salts to
remove calcium |
| USES |
Coagulation tests (protime
and prothrombin time), full draw
required |
| Dark Green Top
|
|
| ADDITIVE |
Sodium heparin or lithium
heparin |
| MODE OF ACTION
|
Inactivates thrombin and
thromboplastin |
| USES |
For lithium level, use
sodium heparin
For ammonia level, use sodium or lithium
heparin |
| Dark Blue Top
|
|
| ADDITIVE |
Sodium EDTA |
| MODE OF ACTION
|
Forms calcium salts
Tube is designed to contain no contaminating
metals |
| USES |
For lithium level, use
sodium heparin
Trace element testing (zinc, copper, lead,
mercury) and toxicology |
| Light Gray Top
|
|
| ADDITIVE |
Sodium fluoride and
potassium oxalate |
| MODE OF ACTION
|
Antiglycolytic agent
preserves glucose up to 5 days |
| USES |
For lithium level, use
sodium heparin
Glucoses, requires full draw (may
cause hemolysis if short draw) |
| Yellow Top |
|
| ADDITIVE |
ACD
(acid-citrate-dextrose) |
| MODE OF ACTION
|
Complement inactivation
|
| USES |
HLA tissue typing,
paternity testing, DNA studies |
| Yellow - Black Top
|
|
| ADDITIVE |
Broth mixture
|
| MODE OF ACTION
|
Preserves viability of
microorganisms |
| USES |
Microbiology - aerobes,
anaerobes, fungi |
| Black Top |
|
| ADDITIVE |
Sodium citrate (buffered)
|
| MODE OF ACTION
|
Forms calcium salts to
remove calcium |
| USES |
Westergren Sedimentation
Rate; requires full draw |
| Orange Top |
|
| ADDITIVE |
Thrombin |
| MODE OF ACTION
|
Quickly clots blood
|
| USES |
STAT serum chemistries
|
| Brown Top |
|
| ADDITIVE |
Sodium heparin
|
| MODE OF ACTION
|
Inactivates thrombin and
thromboplastin |
| USES |
Serum lead determination
|
|
|
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