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Chapter 9
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Pre-examination/ pre-analytical phase of testing
Begins when test is order & ends when testing begins.
Skills needed in phlebotomist:
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Technical skills to perform blood draw
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Recognize preanalytical factors & address them
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Reference Ranges / Intervals
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Tests confirm health or screen, diagnose, & monitor disease.
Tests results are compared with specimens of healthy people.
Reference ranges or intervals
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Consist of range of values with high and low limits
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Often based on healthy, fasting people
Delta check compares pateint’s current and previous test results.
Basal state
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Vascular access devices and sites
Basal state: resting sate of body in morning after 12 hrs fasting.
Basal-state specimen
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Ideal for reference ranges on inpatients.
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Effects of diet, exercise, on test result are minimized.
Factors influencing basal state: age, sex, conditions of body
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Physiologic variables
VARIABLE
Age
Altitude
Dehydration
Diet
Circadian variation
Drug theraphy
Exercise
Fever
Sex
Intramuscular injection
Jaundice
Position
Pregnancy
Smoking
Stress
Environmentak factors
EFFECT/ TEST AFFECTED
RBC, WBC, Creatinine clearance, hormones
Increased: RBC, Hgb, Hct, CRP, uric acid
Decreased: ruined creatinine, renin
Causes hemoconcentration
Increases RBC, enzymes, Fe, Ca, Na, K coag
factros
Glucose, lipids, electrolytes
TSH, cortisol, Fe
Enzyme hormones
pH, PCO2, CK, LDH, glucose
Hormones, cortisol, insulin
RBC, Hgb, Hct
CK, LDH
Abone,al yellow color can interfere in tetsing
Aldosterone, bilirubin, blood cells, ca, K
Lowers RBC
Chol, cortisol, glucose, GH, triglycerides, RBC,
WBC
WBC, Fe, ACTH, catecholamines, cortisol
Acute heat exposure increases plasma volume
Excessive sweating increases
hemoconcentration
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Burns, scars, and tattoos
Veins difficult to plapate; impaired circulation; new burns
are painful; tattoos may be more susceptible to infection
and dyes may interfere.
Damaged veins
Difficult to palpate & yield erroneous results
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Sclerosed- hardened vein
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Thrombosed- clotted veins
Mastectomy
Surgical breast removal
Lymph flow obstructed with node removal; swelling present
Tourniquet can cause injury
Can change blood composition
Intravenous (IV) Line
Catheter inserted in peripheral vein
Avoid drawing blood from arm containing IV
IV Catheter lock
Needless connection device in form of stopcock or cap
Saline lock
Heparin lock (heplock)
Previously active IV sites
Potential source of testing error
Wait 24 to 48 hours
Arterial line (A-line or art-line)
Catheter placed in an artery (usually radial)
Provides accurate & continuous measurement of blood
pressure
No tourniquet or venipuncture in arm with an arterial line
Arteriovenous (AV) shunt/ fistula/ graph
Permanent, surgical fusion of an artery and vein
Created for dialysis access
Located in back of arms above wrist
Central vascular access devices (CVADS)
Known as indwelling lines
Consist of tubing inserted into main vein or artery
Used for administering fluids & medications
For monitoring pressures & drawing blood
Types of CVADs
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Problem sites
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Obesity
Obese vein may be deep and hard to find
Use longer or bariatric tourniquet
try median cubital or cephalic veins
Paralysis
Avoid drawing blood from paralyzed arm
Increased chance of thrombosis
Difficult to detect nerve injury
Edema
Swelling caused by accumulation of fluid in tissues
Results when fluid IV infiltrates surrounding tissues
Contaminates blood with tissue fluid
Veins are harder to locate and tissue is fragile
Hematoma
Swelling or mass of blood
Caused by blood leaking from vessel during venipuncture
painful, contaminate blood sample, obstruct blood flow
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Central venous catheter (CVC) or line
Inserted into large veins (subclavian)
Advanced into superior vena cava
Exit & tunneled under skin several inches away
One or more lengths of capped tubing protrude from exit
site
Implanted port
Small chamber attached to indwelling line
Surgically implanted under skin (upper chest or arm)
Self-sealing chamber located by palpating skin & accessing
with a special needle
Peripherally inserted central catheter (PICC)
Inserted in veins of extremities (AC vein) & threaded into
main vein leading to the heart
Does not require surgical insertion
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Blood sampling device
Connected to arterial or CVC to collect blood
Reduces chance of infection
Prevents needlesticks
Minimizes waste from line draw
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Only nurses or specially trained personnel are allowed to draw
blood from vascular access devices (VADs) & Phlebotomist only
assist.
Patient complications and conditions
Allergies to equipment & supplies
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Adhesive allergy
Place gauze square over site and have patient remove in 15
minutes. Or have patient apply pressure for 5 mins instead
of bandage.
Antiseptic allergy
Use alternate antiseptic
Latex allergy
Look for sign indicating latex allergy on patient’s door or ask
Use nonlatex equipment (gloves, tourniquet, bandages)
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Patient complications and conditions
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Excessive bleeding
Patients on aspirin or anticoagulant may bleed longer
Maintain pressure until bleeding stops
If bleeding continues for > 5 minutes, notify personnel
Fainting (syncope)
Loss consciousness & postural tone
Caused by insufficient blood flow to brain
patients w/ history of fainting lie down during venipuncture
Lower patient’s head & apply cold compress to back of neck
Nausea and vomiting
Discontinue blood draw until feeling subsides
Give patient nemesis basin or wastebasket
Pain
Warn patient before needle insertion
Avoid excessive, deep, blind, or lateral redirection of needle
Extreme pain or numbness indicates nerve involvement;
remove needle immediately, apply ice, document incident
Petechiae
Tiny, nonraised red spots
Appear on arm when tourniquet is applied.
Jaundice
Indicate liver inflammation cause by hepa B or C virus
Seizures/ convulsions
Discontinue draw immediately; Hold pressure over site
without restricting patient’s movement
Do not put anything in patient’s mouth; Protect patient from
self-injury; Notify first-aid personnel
Procedural Error and Specimen Quality Concerns
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Hematoma formation and bruising
Discontinue draw immediately & hold pressure for 2 mins.
Offer cold compress or ice pack if large and swollen
Iatrogenic anemia
Anemia brought about by blood loss from draws
Life is threatened if >10% blood volume is removed at once
Hemoconcentration
Decrease in fluid content of blood and increase in
nonfilterable large molecules
Caused by stagnation of normal venous flow due to
tourniquet
Hemolysis
Damage or destruction of RBCs
Hemoglobin escapes into fluid part of specimen
Partially filled tubes (short draw)
Blood-to-additive ratio may be incorrect if underfilled
Specimen contamination
Allowing alcohol residue, fingerprints, glove powder, urine in
newborn screening ssmalles, dripping perspiration into
capillary specimen, etc.
Wrong or expired collection tube
Troubleshooting failed venipuncture
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Procedural Error Risks
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Collect only minimum required specimen volumes
Inadvertent arterial puncture
Signs include rapidly forming hematoma and blood filling
tube quickly
Infection
Avoid by doing the ff:
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Don’t open tape or bandages ahead of time
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Don’t preload needles onto tube holders
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Don’t touch needle insertion site after sterilizing
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Minimize time between needle cap removal &
venipuncture
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Remind patient to keep bandage on at least 15
minutes.
Nerve injury
If initial vein entry in unsuccessful, use slight fordward or
backward redirection of needle.
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Claw hand- abnormal hand position due to ulnar
nerve injury
Reflux of additive
Blood flows back into vein form collection tube
Tube additive may cause adverse reaction
Keep arm in downward position & tube below puncture site
Vein damage
Avoid numerous venipunctures in same area over time
Avoid blind probing and improper technique
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Tube position
Improper seating
Needle fails to penetrate stopper
Needle position
Needle not inserted far enough
Bevel partially out of skin
Bevel partially into vein
Bevel partially through vein
Bevel completely through vein
Bevel against vein wall
Bevel in valves
Needle beside vein
Undetermined position
Collapsed vein
Vein walls draw together temporarily, shutting off blood flow
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Caused by: too strong vacuum, tight tourniquet or too close
to site, tourniquet is removed during draw.
Tube vacuum
Loss of vacuum due to bevel partially out of skin
Loss of vacuum due to damage of tube
Enumeration:
Problem sites
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2.
3.
4.
5.
6.
7.
Burns, scars, and tattoos
Damaged veins
Mastectomy
Obesity
Paralysis
Edema
Hematoma
Vascular access devices and sites
1.
2.
3.
4.
5.
Intravenous (IV) Line
IV Catheter lock
Previously active IV sites
Arterial line (A-line) or art-line)
Arteriovenous (AV) shunt/ fistula/ graph
Procedural Error and Specimen Quality Concerns
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2.
3.
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5.
Hemoconcentration
Hemolysis
Partially filled tubes (short draw)
Specimen contamination
Wrong or expired collection tube
Patient complications and conditions
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2.
3.
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5.
6.
7.
Excessive bleeding
Fainting (syncope)
Nausea and vomiting
Pain
Petechiae
Jaundice
Seizures/ convulsions
Procedural Error Risks
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2.
3.
4.
5.
6.
7.
Hematoma formation and bruising
Iatrogenic anemia
Inadvertent arterial puncture
Infection
Nerve injury
Reflux of additive
Vein damage
Procedural Error and Specimen Quality Concerns
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2.
3.
4.
5.
Hemoconcentration
Hemolysis
Partially filled tubes (short draw)
Specimen contamination
Wrong or expired collection tube
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