•many errors can occur during these steps, such errors areconsidered 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 standardizationof collection, transport, and processing of specimens.

2. Uncontrollable variables are those associated with thephysiology of the particular patient (age, sex, underlyingdisease, 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

1.Appearance2.Attitude3.Communication Skills4.Bedside Manner

PROFESSIONALISM

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

ARTERIES •Have thick walls to withstand the pressure of ventricular contraction, that creates a pulse•Normal systemic arterial blood is bright red.

VEINS•have thinner walls because blood in them is under less pressure•Collapse more easily•Dark bluish red (oxygen poor)

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 theseare 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 sitechloride, 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 gaugeGauge = 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

•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 vacuumtube 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

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 requests2. Approach, identify and prepare the patient3. Verify diet restrictions and latex sensitivity test4. Sanitize hands5. Position patient, apply tourniquet and ask patient to make a fist6. Select vein,release tourniquet and ask patient to open fist7. Clean and air dry site8. Prepare equipment and put on gloves9 .Reapply tourniquet, uncap and inspect needle10. Ask patient to remake a fist ,anchor vein and insert needle11. Establish blood flow, release tourniquet and ask patient to open fist

12. Fill, remove and mix tubes in order of draw13. Place gauze, withdraw needle, activate safety feature and apply pressure14. Discard needle and holder unit15. Label tubes16. Observe Handling Instructions17. Check patient’s arm, apply bandage18. Dispose of used materials19. Thank Patient, Remove Gloves and Sanitize hands.20. Transport Specimens to the lab.

Trouble shooting Failed Venipuncture

Tube positionVacuumBevel against the vein wallNeedle too deepNeedle beside the veinCollapsed vein

Blood cannot be replaced as quickly as it is drawn

 Use a smaller tube or pull the plunger more slowlyIf 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

Geriatric Venipuncture

•Interaction with a child•Immobilizing a child

• 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 anemia3. Inadvertent arterial puncture4. Infection of the site5. Nerve injury6. Reflux7. Vein damage

Patient Conditions and Complications

1.Allergies to supplies or equipments2.Excessive bleeding3.Fainting (syncope)4.Nausea or vomiting5.Obese Patients6.Pain7.Petechiae8.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 22.Heels - infants

Materials:

1.Alcohol- 70 % alcohol2.Gauze- to wipe the first drop of blood and excess tissue fluid

- hold the pressure after specimen collection3. Bandage – to cover the site after collection4. Lancets - sterile, disposable, sharp instruments used for capillary puncture5. 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 hematocrit8. Sealants – used to seal one end of microhematocrit tubes

Capillary Order of Draw

1.EDTA specimens – first because most affected by clumping2.Other additive specimes3. 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 venipuncture5. Position patient6. Select puncture/ incision site7. Warm the site if applicable8. Clean and air dry site9. Prepare equipment10. Puncture the site and Discard the lancet\11. Wipe away first drop of blood12.Fill and mix tubes in the order of draw13. Place gauze and apply pressure14. Label specimen and observe special handling procedures15. Check the site and apply bandage16. Dispose of used materials17. Thank patient, Remove Gloves and sanitize hands18. 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