Specimen Collection-Part 1 W6:L1

Plasma:

the liquid portion

Platelets:

the clot forming components

White Blood Cells:

the infection fighters

Red Blood Cells:

the oxygen transporters

Sources for blood collection:

•Venous: most common, composition varies by site,
impaired blood flow affects analytes

•Arterial: used for blood gas analysis

•Capillary: “finger puncture” contains mixture of arterial and venous blood (arterial portion is higher), collection technique is critical

Which of these are MLTs allowed to collect?

only venous and capillary

Venipuncture:

the process by which a blood specimen is obtained from a patient’s vein

Phlebotomy:

the removal of blood from a vein

Draw:

the quantity of blood withdrawn

Phlebotomists:

trained personnel that specialize in blood collection

Capillary Puncture:

Skin puncture using a lancing device

Why do MLTs need to know about the collection process?

• MLTs perform phlebotomy in smaller laboratories and in many private laboratories

• The perfect analysis means nothing if the sample is compromised!!

• GARBAGE IN = GARBAGE OUT!!

• Highly regulated area (licensing and accreditation).

• The MLT is accountable for the accuracy of a result when s/he
verifies and/or reports the result!!

Requirements of Specimen Collection:

-Professionalism
-Patient Consent
-Confidentiality

Components of a Venipuncture:

• Getting the order, collection labels
• Gathering supplies
• Locating in-house patient, chair for out-patient collections
• Patient ID
• Cleaning hands/Choosing the collection site
• Assembling the equipment• Needle and holder
• Tourniquet
• Cleansing the site
• Tubes (types, function, order of draw)
• Tubes Labelling
• Waste disposal
• Taking care of the patient
• Handwashing
• Transporting collected tubes

Patient ID:

- the most critical step in the collection process!
PATIENTS have unique identifier numbers (Admission numbers in
hospitals

SAMPLES have unique identifier numbers (Lab numbers)

Patient ID requirements:

In Hospital:
• Ask name of patient (spell)
• Check arm band (wristband) to ensure the same
name as the collection label
• Check patient (admin) unique number: must
confirm that it is the same number as on the
collection label

• Out Patient Setting:
• Also ask date of birth, or health card no.

U.S. uses a “3-way ID” for patient ID:

• Patient must provide verbal ID (states their name)
• ID band (wristband) MUST be checked
• Labeled tubes checked against wristband

Sleeping Patients: What should you do?

• Wake up gently, don’t startle (affects test results)
• Don’t turn on bright lights (warn person first)
• NEVER collect from a sleeping person
• Don’t forget you need to provide informed consent, get consent, and confirm identity (wristband)

Unconscious Patients: What should you do?

• Often in ER/ICU
• Ask relative, nurse, physician to identify person
• Still requires wristband to validate identity
• Speak to person as if conscious
• Follow policies!

Cleaning hands during phlebotomy:

CDC (Center for Disease Control): Use alcohol-based
waterless antiseptic agent for routine decontamination of hand, if not visibly soiled. Waterless antiseptic agents are preferable

Venipuncture primary location:

Antecubital fossa: triangular area on the anterior view of the elbow of a human (the elbow “pit”)

Contains three veins:
• Median cubital vein
• Cephalic vein
• Basilic vein

Always check median cubital vein first!

Palpate: To examine or explore by touching (an organ
or area of the body), usually as a diagnostic aid

PALPATE across the area to locate a vein. Then
palpate up and down the vein to determine its
direction

Order of choosing veins based of CLSI:

1. median cubital (on both arms)
2. cephalic vein
3. basilic vein (if no other choice)

Because the basilic vein is too close to the brachial artery and several nerves. Improper collection can lead to damage to theartery or nerve damage.

CLSI: CLINICAL AND LABORATORY STANDARDS INSTITUTE

3 types of antecubital vein patterns:

-H-pattern
-M-pattern
-Atypical pattern

If the arm is unavailable:

1. dorsal hand veins
2. foot veins
3.. subclavian vein
4. femoral vein or artery

Inappropiate sites:

-arms on side of mastectomy
-edematous areas
-hematomas
-arms in which blood is being transfused
-scarred areas
-arms with fistulas or vascular grafts
-sites above an IV cannula

If you need to collect from above an IV arm:

IV will dilute blood and add IV
contents
•Have nurse shut off IV for at least
3 min
•Discard first 5 mL (10mL for coag)
•Collect blood work
•Have nurse restart IV
•Note on requisition “Drawn from
IV arm, IV shut off and 5mL
discarded”.

Location a Vein:

• Position arm down (uses force of gravity as an aid)
• Instruct patient to make a fist
• Palpate across the arm using your forefinger, checking for a bounce back
after release
• Remember to check BOTH arms

Phlebotomy Chair:

• Often used in out-patient setting
• Require sturdy backrest, arm support, restraint system
equire
TWO arms to prevent falls after syncope• Ammonia inhalants NOT recommended (asthmatics)
• Some chairs recline to lie down

Venipuncture Equipment:

• Needle
• Tube Holder
• Tourniquet
• Evacuated tubes
• Gauze
• Alcohol Swabs
• Tape
• Gloves

The Evacuated Tube System or ETS:

• Requires needle, tube holder, evacuated tubes
• Tubes have premeasured vacuum that automatically draws the
volume of blood indicated on the label

Anatomy of a Needle:

-Gauge: refers to the size of the Bore (opening)
the smaller the gauge number, the larger the bore size
-Bevel end (slanted): prevents "coring" removing a piece of the skin or vein

-Lumen: (internal space of the needle)

-Hub: end that attaches to holder

Multi-sample needle:

allows for several tubes to be collected with one needle puncture

Tourniquet:

a mechanical device used on the surface of an extremity (arm) to compress veins prior to venipuncture, enlarging them by preventing the return of blood to the heart and lungs

Distends (swell or cause to swell by pressure from inside) veins and makes them easier to find and pierce with a needle

-latex-free, single use
tight enough to restrict venous flow but not too tight to restrict arterial flow

Tourniquet complications:

-inappropriate application of a tourniquet can change the concentration of many analytes
Causes:

-venous stasis
-hemoconcentration

*Hemoconcentration: (when tourniquet left on too long)

the plasma portion of the blood filters into the tissue
this causes an increase in the proportion of cells remaining in the vein and an alteration in the ratio of elements in the blood being drawn
-should be release within 1 minute

Ways to reduce hemoconcentration:

-choose an appropriate vein
-have patient release fist immediately upon blood flow
-do not have patient pump their first
-do not excessively massage vein
-do not probe with the needle

Prolonged application of tourniquet can also lead to the presence of

petechiae; small non-raised red spots on the skin
-common in patients with capillary wall or platelet disorders

Disinfectant:

agent used to clean a surface other than human tissue

Antiseptic:

agent used to clean living tissue
• Prevents sepsis or infection
• Used to clean patient’s skin prior to insertion of a needle to prevent contamination from normal skin flora

Bacteriostatic:

inhibits bacterial growth (doesn’t kill)

Cleansers:

• 70% isopropyl alcohol (rubbing alcohol): routine phlebotomy
• Povidone-iodine solution (Betadine): arterial punctures and blood cultures
• Benzalkonium chloride, Chlorhexidine gluconate: blood cultures and arterial punctures (used for patients sensitive to iodine)

harsh chemicals should be washed off with alcohol at end

Evacuated tube system:

tubes have a vacuum in them
• Once punctured, the vacuum pulls the blood into the tube
The vacuum is designed to fill the tube to a designated “fill
volume”
• Once punctured, the tube cannot be re-used!

If the vacuum is designed to fill automatically to the fill volume,
how does a tube become overfilled?

If MLT, combines two half full blood tubes into one, it will go over max and completely give a wrong additive ratio

Or old tubes that vacuum sealed is not working properly and gets less blood than needed

Additive:

a chemical added to a specimen that changes one or more
of its physical or chemical properties, any substance placed within the tube other than the stopper

-prevents clotting
-preserve blood components
-increase clotting time

Anticoagulant:

a substance that can suppress, delay, or prevent
coagulation of blood (one type of additive)

Preservative:

chemical that prevents a change in the concentration of
analytes in blood, urine, or other body fluid

Coagulation (Clotting):

When blood leaves the veins, it will come in contact with factors that will initiate the formation of a blood clot

the sequential process by which the multiple coagulation factors of blood interact in the coagulation cascade, resulting in the formation of a fibrin clot

Whole blood :

Cells + plasma

Plasma:

• Anti-coagulated fluid
• Contains fibrinogen

Serum:

• Coagulated fluid
• Does NOT contain fibrinogen

Plasma:

is the liquid, cell-free component of blood. It has been treated with anti-coagulants
anticoagulated

Serum:

is the liquid component of blood AFTER coagulation has
occurred. It lacks clotting factors such as fibrinogen
Clotted

serum:

=plasma - fibirnogen

Centrifugation Time:

Recommended: 10 min @1000-2000g

How long should serum sample stand before centrifugation?

•Plain red top: 45-60 min for clot to form
•SST: min 30 min

Plasma take no time because blood has anti-coagulates