•many errors can occur during these steps, such errors are
considered preanalytical errors and are known to
contribute to delayed and suboptimal patient care.
PHLEBOTOMY AND SPECIMEN CONSIDERATIONS
Two classifications of preanalytical variables:
1. Controllable variables relate to standardization
of collection, transport, and processing of specimens.
2. Uncontrollable variables are those associated with the
physiology of the particular patient (age, sex, underlying
disease, etc.)
PHLEBOTOMY AND SPECIMEN CONSIDERATIONS
PHLEBOTOMY
•The process of collecting blood
•literally translated means “to cut a vein”
PHLEBOTOMY AND SPECIMEN CONSIDERATIONS
2 main phlebotomy procedures:
1. Venipuncture- blood is collected through a
needle inserted in the vein
2. Capillary puncture –blood is collected from a
skin puncture made with a lancet or similar device
•individuals trained
in blood collection
techniques
BLOOD COLLECTION PERSONNEL
•Plays an important role in public relations in the laboratory
•An assured professional can put the patient at ease and facilitate a
positive interaction
BLOOD COLLECTION PERSONNEL
PROFESSIONALISM
1.Appearance
2.Attitude
3.Communication Skills
4.Bedside Manner
INFECTION CONTROL
•PPE
-lab coats, gloves are required for phlebotomy procedures
and during specimen handling
-New gloves for each patient
-Masks
•Hand hygiene
-most important means of preventing the spread of infection
-Hands must be decontaminated frequently , including after
glove removal
-Alcohol based antiseptic can be used if hands are not visibly
soiled
•Isolation
- separates certain patients from others and limit their contact
with personnel and visitors
-Required precaution is posted on patient’s door
THE VASCULAR SYSTEM
VEINS
•have thinner walls because blood in
them is under less pressure
•Collapse more easily
•Dark bluish red (oxygen poor)
ARTERIES
•Have thick walls to withstand the
pressure of ventricular contraction, that
creates a pulse
•Normal systemic arterial blood is
bright red.
Capillary
• only one cell
•Can easily be punctured to provide
blood specimen
VASCULAR ANATOMY (phlebotomy related)
2 basic patterns of the veins
VASCULAR ANATOMY (phlebotomy related)
VASCULAR ANATOMY (phlebotomy related)
OTHER VEINS:
•Veins on the back of the hand or at the ankle may be used,
although these
are less desirable and should be avoided in diabetics and other
individuals with poor circulation.
•Leg, ankle and foot veins are sometimes used but not
without permission of the patient’s physician due to potential
medical complications
SOURCE AND COMPOSITION OF BLOOD SPECIMENS
ARTERIAL BLOOD
Primarily reserved for blood gas evaluation and certain emergency situations
VENOUS BLOOD
•affected by metabolic activity of the tissue it drains and varies by collection site
chloride, glucose, pH, CO2, lactic acid and ammonia levels differ may from
arterial blood
CAPILLARY BLOOD
•Contains arterial and venous blood plus tissue fluid
•Capillary glucose is normally higher
•Calcium, potassium and total protein are normally lower
TYPES OF BLOOD SPECIMENS
SERUM
PLASMA
WHOLE BLOOD
VENIPUNCTURE EQUIPMENT
Venipuncture can be performed by 3 basic
methods
I Evacuated tube system (ETS)
– most preferred because blood is
collected directly from the vein in the tube, minimizing the risk of specimen
contamination and exposure to the blood
II Needle and syringe – used on small, fragile and damaged veins
III Winged infusion set (butterfly) – can be used with the ETS and
syringe
•Used to draw blood from infants and children, hand veins and other difficult to
draw situations
VENIPUNCTURE EQUIPMENT
1. Tourniquet
•Applied to a patient’s arm during venipuncture
•Distends the veins, making them larger and
easier to find, stretches the wall so they are
thinner and easier to find
•Must not be left on longer than 1 minute
because specimen quality may be affected
VENIPUNCTURE EQUIPMENT
2. Needles
•Sterile, disposable and sized by length and gauge
Gauge = number that relates to needle
diameter or bore
• Gauge 21-23
•Gauge 21 – considered standard for routine
venipuncture
VENIPUNCTURE EQUIPMENT
3. Evacuated Tube System
3 basic components
A. Multisample needle – allows collection of
multiple tubes during venipuncture
VENIPUNCTURE EQUIPMENT
•The Vacuum collection needle is pointed at both ends, with one end
shorter than the other.
•The long end of the needle is used for insertion into the vein, the
shorter end is used to pierce the rubber stopper of the vacuum
tube and usually is covered by a rubber sheath
VENIPUNCTURE EQUIPMENT
•The bevel is the slanted opening at the end of
the needle.
•bevel of the needle must face upward when
the needle is inserted into the vein.
VENIPUNCTURE EQUIPMENT
B. Tube holder
•Plastic cylinder with a small opening for a needle at one end and a
large opening for tubes at the other end
•The tube end has flanges to help place and remove tubes
VENIPUNCTURE EQUIPMENT
C. Evacuated tubes
•Have a premeasured vacuum that automatically draws the
volume of blood indicated on the label
•Vacuum loss can occur if tubes are stored improperly,
opened, dropped or advanced too far onto the needle
before draw, or if the needle bevel backs out of the skin
during draw
•Are color coded to identify a type of additive, absence of
additive or special tube property
VENIPUNCTURE EQUIPMENT
4. SYRINGE SYSTEM
•Syringes are customarily used for patients with veins from which it is
difficult to collect blood and for blood gas analysis.
VENIPUNCTURE EQUIPMENT
5. BUTTERFLY SYSTEM
•A short needle with butterfly wings and a length of tubing with a Luer fitting for
syringe use or a Luer adapter for ETS use
•Gauge 23 most commonly used
•During use , the plastic wings are held with the thumb and index finger,
allowing the user to achieve the shallow needle angle needed to access small
veins
VENIPUNCTURE EQUIPMENT
6. Tube Additives
A. Anticoagulants
•Prevent blood from clotting and include EDTA, citrates, heparin and oxalates
B. Antiglycolitic agents
•Prevent glycolysis which can decrease glucose concentration by upto 10 mg/dl
per hour
•Sodium fluoride : most common antiglycolitic agent
Preserves glucose for upto 3 days, and inhibits bacterial growth
C. Clot activators
•Are coagulation factors like thrombin
•Glass particles (silica)
•Inert clays ex. Diatomite (celite)
Enhance clotting by providing more surface for platelet activation
VENIPUNCTURE EQUIPMENT
D. Thoxotropic gel separators
-inert substances contained near the bottom of certain tubes
-during centrifugation the gel lodges between cells and fluid, forming a
physical barrier that prevents the cells from metabolizing substances in
the serum or plasma
VENIPUNCTURE EQUIPMENT
7. Trace element free tubes
•Contamination free
•Used to collect specimens for trace elements, toxicology, nutrient
ORDER OF DRAW AND ADDITIVE CARRY OVER
•is a special sequence of tube collection that
reduces the risk of specimen contamination
by microorganisms
Additive carry over
•Affects chemistry test
•Occurs when blood in an additive tube touches the needle during
venipuncture or during transfer from a syringe
ORDER OF DRAW AND ADDITIVE CARRY OVER
COMMON TESTS AFFECTED BY ADDITIVE CONTAMINATION
Citrate – ALP, Ca,Phosporus
EDTA - ALP, Ca, CK,PTT,K,PT,Serum Iron, Na
Heparin – Activated CT, ACP, Ca, PT, PTT Na, Li
Oxalates- ACP, ALP, Amylase,Ca, LDH, PT, PTT, K, Red cell
Silica (clot activator) – PTT, PT
Sodium fluoride – Na, BUN
STOP, LIGHT RED, STAY PUT,
GREEN LIGHT, GO
S (Sterile)
L (Light Blue)
R (Red)
S (Serum Separator Tube)
P (Plasma Separator tube)
G (green)
L (lavender)
G (gray)
VENIPUNCTURE PROCEDURES
1. Review and accession of test requests
2. Approach, identify and prepare the patient
3. Verify diet restrictions and latex sensitivity test
4. Sanitize hands
5. Position patient, apply tourniquet and ask patient to make a
fist
6. Select vein,release tourniquet and ask patient to
open fist
7. Clean and air dry site
8. Prepare equipment and put on gloves
9 .Reapply tourniquet, uncap and inspect needle
10. Ask patient to remake a fist ,anchor vein and insert
needle
11. Establish blood flow, release tourniquet and ask
patient to open fist
12. Fill, remove and mix tubes in order of draw
13. Place gauze, withdraw needle, activate
safety feature and apply pressure
14. Discard needle and holder unit
15. Label tubes
16. Observe Handling Instructions
17. Check patient’s arm, apply bandage
18. Dispose of used materials
19. Thank Patient, Remove Gloves and
Sanitize hands.
20. Transport Specimens to the lab.
Trouble shooting Failed Venipuncture
Tube position
Vacuum
Bevel against the vein wall
Needle too deep
Needle beside the vein
Collapsed vein
Blood cannot be replaced as quickly as it is
drawn
Use a smaller tube or pull the plunger more
slowly
If blood does not return, discontinue the
draw
Undetermined needle position
Multiple venipuncture attempts:
•Try again below the first site, on the other arm or
on a hand or wrist vein.
•If the second attempt is unsuccessful, ask
someone to take over.
Pediatric Venipuncture
•Interaction with a child
•Immobilizing a child
Geriatric Venipuncture
• meaningful communication is important
•Alzheimer’s disease, arthritis, coagulation problems,
clouding of lens or catarcts, hearing loss, skin are less
elastic, parkinson’s disease and stroke
Preanalytic Considerations
Problem sites:
•Burn, Scars and Tattoos
•Damaged Veins
•Edema
•Hematoma
•Mastectomy
Vascular Access Devices:
•Arterial line
•Arteriovenous shunt or fistula
•Heparin or saline lock
•Intravenous line
•Central Vascular access device
(CVAD) or indwelling line
PROCEDURAL ERROS RISKS
1. Hematoma formation
- rapid swelling near the venipuncture site due to blood leaking into the
tissues
Situations that can trigger hematoma formation?
2. Iatrogenic anemia
3. Inadvertent arterial puncture
4. Infection of the site
5. Nerve injury
6. Reflux
7. Vein damage
Patient Conditions and Complications
1.Allergies to supplies or equipments
2.Excessive bleeding
3.Fainting (syncope)
4.Nausea or vomiting
5.Obese Patients
6.Pain
7.Petechiae
8.Seizures/Convulsions
Capillary Specimen Collection
-Useful in pediatrics where removal of larger quantities
of blood can have serious consequences
Collection sites
1. Fingers – adults and children over the age of 2
2. Heels - infants
Materials:
1. Alcohol- 70 % alcohol
2. Gauze- to wipe the first drop of blood and excess
tissue fluid
- hold the pressure after specimen collection
3. Bandage – to cover the site after collection
4. Lancets - sterile, disposable, sharp instruments used
for capillary puncture
5. Warming devices – increases blood flow when
performing heel sticks
ex. Towel or diaper dampend with warm
water (<42C)
6. Microcollection Tubes – special small plastic tubes
“bullets”
7. Microhematocrit tubes – used for manual hematocrit
8. Sealants – used to seal one end of microhematocrit
tubes
Capillary Order of Draw
1. EDTA specimens – first because most affected by
clumping
2. Other additive specimes
3. Serum specimens
Indications for capillary puncture:
Adults and Older Children:
•There are no accesible veins
•Available veins are fragile and must be saved for other
procedure
•Patient has clot-forming tendencies
•Blood is to be obtained for POCT procedures
Infants and Very Young Children:
•Infants have a small blood volume
•Venipuncture is difficult and can damage vein and
surrounding tissues
•Preferred specimen for newborn screening test
Capillary Specimen Collection
Steps 1-4 same as venipuncture
5. Position patient
6. Select puncture/ incision site
7. Warm the site if applicable
8. Clean and air dry site
9. Prepare equipment
10. Puncture the site and Discard the lancet\
11. Wipe away first drop of blood
12.Fill and mix tubes in the order of draw
13. Place gauze and apply pressure
14. Label specimen and observe special handling procedures
15. Check the site and apply bandage
16. Dispose of used materials
17. Thank patient, Remove Gloves and sanitize hands
18. Transport specimen to the lab
Heel Stick procedure
•Select a site on the medial or lateral plantar surface of
the heel that is warm, normal color, free of cuts, bruises,
infection, rashes, swelling or previous punctures
•Encircle the heel with the index finger around the
arch, thumb around the bottom and other fingers
around the top of the foot
•Place the lancet against the skin on the medial or
lateral plantar surface of the heel using enough
pressure to keep it in place without deeply
compressing the skin
•Neonatal Bilirubin Collection – must be protected from
light
•Neonatal Screening
•screens for
phenylketonuria, a
disorder which could be
managed by dietary
adjustment if diagnosed
early.
Specimen Handling and Processing
• Mixing tubes – gentle inversion
•Transporting Specimens
•Delivery time limits
- must be centrifuged within 1 hour if
serum or plasma is needed
Why is prompt separation important?
•Cellular glycolysis lowers glucose levels in a
specimen at a rate of up to mg/L per hour until
the serum or plasma is physically separated
from the cells