Chapter 09 Preanalytical Considerations

Copyright © 2016 Wolters Kluwer Health | Lippincott Williams & Wilkins
Chapter 9: Preanalytical
Considerations

Copyright © 2016 Wolters Kluwer • All Rights Reserved
Objectives
1. Demonstrate basic knowledge of the preanalytical
variables that influence laboratory test results, define
associated terminology, and identify the tests most
affected by each one.
2. Discuss problem areas associated with site selection
including various vascular access sites and devices, and
explain what to do when they are encountered.
3. Describe how to handle patient complications and
conditions pertaining to blood collection, address
procedural error risks, and specimen quality concerns,
and analyze reasons for failure to draw blood.

Overview
• Preanalytical Phase of Testing
– Begins when test is ordered
– Ends when testing begins
• Skills Needed in Phlebotomist
– Technical skills to perform blood draw
– Ability to recognize preanalytical factors & address them

Overview (cont.)
• Topics Presented in Chapter 9
– Physiological variables
– Problem venipuncture sites
– Types of vascular access devices
– Patient complications & conditions
– Procedural errors
– Specimen quality issues
– Troubleshooting failed venipuncture

Reference Ranges/Intervals
• Tests confirm health or screen, diagnose, & monitor
disease
• Test results are compared with specimens of healthy
people
• Consist of range of values with high & low limits
• Most often based on healthy, fasting people
One way a physician evaluates a patient’s test results is by
comparing them to reference ranges and, if available,
previous results on the same patient.

Basal State
• Definition: resting state of body early in morning
after fasting 12 hours
• Basal-state specimen
– Ideal for establishing reference ranges on inpatients
– Effects of diet, exercise, etc. on test result are minimized
• Basal state is influenced by:
– Age
– Gender
– Conditions of body

Physiological Variables
Variable Has Effect on
Age RBC, WBC, creatinine clearance
Altitude RBC
Dehydration Hemoconcentration, RBC, enzymes, Fe, Ca, Na
Diet Glucose, lipids, electrolytes
Diurnal variation TSH, cortisol, Fe
Drug therapy Enzymes, hormones
Exercise/IM injection pH, PCO2, CK, LDH, glucose
Fever Hormones, cortisol
Gender RBC, Hgb, Hct
Jaundice Yellow color interferes
Position Protein, K
Pregnancy RBC
Smoking Chol, cortisol, glucose, GH, triglyceride, WBC
Stress WBC, Fe, ACTH, catecholamine, cortisol
Temperature and humidity Hemoconcentration
Match physiological effects with lab
tests in WORKBOOK Activity 9-2.

Jaundice
Although there are
a number of
different causes,
jaundice in a
patient may
indicate liver
inflammation
caused by
hepatitis B or C
virus.

Problem Sites
• Burns, Scars, & Tattoos
– Veins are difficult to palpate here
– May have impaired circulation
– New burns are painful
– Tattoos may be more susceptible to
infection; dyes may interfere
• Damaged Veins
– Sclerosed: hardened
– Thrombosed: clotted
– Difficult to puncture & yield erroneous
results
If you have no choice
but to draw in an area
with a tattoo, try to
insert the needle in a
spot that does not
contain dye.
Use another site if
possible, or draw
below (distal to)
damaged veins.

Problem Sites (cont.)
• Edema
– Swelling caused by abnormal
accumulation of fluid in tissues
– Results when fluid from IV
infiltrates surrounding tissues
– Contaminates blood with
tissue fluid
– Veins are harder to locate, & tissue is fragile
• Hematoma
– A swelling or mass of blood
– Caused by blood leaking from vessel during venipuncture
– Can be painful, contaminate blood sample, obstruct blood flow
Phlebotomists on early-
morning rounds in hospitals
or nursing homes are often
the first to notice edema
from infiltrated IVs and
should alert the appropriate
personnel.

Hematoma
(Photo courtesy Sue Kucera.)

Hematoma (cont.)
• Hematomas resulting from venipuncture
After you finish this section, do Matching 9-3 in
the WORKBOOK to see if you can match
problem sites with possible drawbacks.

Problem Sites (cont.)
• Mastectomy
– Surgical breast removal
– Lymph flow is obstructed with
removal of lymph nodes
– Swelling & infection may be present
– Applying tourniquet here can cause injury
– Can change blood composition
• Obesity
– Veins may be deep & hard to find
– Use longer tourniquet & try median cubital or cephalic vein
When a
mastectomy has
been performed
on both sides,
the patient’s
physician should
be consulted to
determine a
suitable site.

Vascular Access Devices and Sites
• Arterial Line
– A catheter placed in an artery
(usually radial)
– Provides accurate & continuous
measurement of blood pressure
– No tourniquet or venipuncture on
an arm with an arterial line
• Arteriovenous Shunt or Fistula
– The permanent, surgical fusion of an
artery & a vein
– Created to provide access for dialysis
– Located on back of arm above wrist
Only nurses and other
specially trained personnel
are allowed to draw blood
specimens from vascular
access devices (VADs).
However, the phlebotomist
typically assists by
supplying the appropriate
tubes, and if a syringe is
used, transferring the
blood to the tubes using a
safety syringe transfer
device.

Arteriovenous Shunt or Fistula

Vascular Access Devices and Sites (cont.)
• Blood Sampling Device
– Connected to arterial or
central venous catheter to
collect blood
– Reduces chance of infection
– Prevents needlesticks
– Minimizes waste from line
draws
(Courtesy of Edwards Lifesciences, Irvine, CA.)

• Heparin or Saline Lock
– A catheter or cannula
connected to a
stopcock/cap w. diaphragm
– Provides access for
administering medicine or
drawing blood
– Placed in vein in lower arm
above wrist for up to 48
hours
– Flushed w. heparin or saline
to prevent clogging

• Intravenous (IV) Sites
– IV line: a catheter inserted in
a vein to administer fluids
– Avoid collecting blood from
arm w. IV
– Blood may be contaminated
w. IV fluid
– If necessary, collect below IV

• Previously Active IV Sites
– Avoid collecting from known previous IV sites for 24 to 48 hours
• Central Vascular Access Devices (CVADs)
– Known as indwelling lines
– Consist of tubing inserted into a main vein or artery
– Used for:
• Administering fluids & medications
• Monitoring pressures
• Drawing blood

• Types of CVADs
– Central venous catheter or line
• Inserted into large vein (subclavian)
• Advanced into superior vena cava
– Implanted port
• A small chamber attached to indwelling line
• Surgically implanted under skin (upper chest or arm)
– Peripherally inserted central catheter
• Inserted in veins of extremities & threaded into central veins

Central Venous Catheter
A: Reprinted with permission from Taylor CR, Lillis C, Lemone P. Fundamentals of Nursing:
The Art And Science Of Nursing Care, 6th ed. Philadelphia, PA: Lippincott Williams &
Wilkins; 2008. B and C: Groshong® and Hickman ® catheters courtesy BARD Access
Systems, Inc., Salt Lake City, UT.

Implanted Port
A: Reprinted with permission from Taylor CR, Lillis C, Lemone P. Fundamentals of Nursing:
The Art And Science Of Nursing Care, 6th ed. Philadelphia, PA: Lippincott Williams &
Wilkins; 2008. B: PowerPort® implanted port, courtesy Bard Access Systems, Inc., Salt
Lake City, UT. C: PowerPort® Duo implanted port, courtesy Bard Access Systems, Inc.,
Salt Lake City, UT.
Copyright © 2016 Wolters Kluwer • All Rights Reserved Copyright © 2016 Wolters Kluwer • All Rights Reserved

Peripherally Inserted Central Catheter
A: Reprinted with permission from Cohen BJ. Medical Terminology, 4th ed. Philadelphia, PA:
Lippincott Williams & Wilkins; 2003. B: PowerPICC® catheter, courtesy Bard Access
Systems, Inc., Salt Lake City, UT.
Test your VAD
knowledge with
Matching Exercise
9-4 and Labeling
Exercise 9-2 in the
WORKBOOK.

Patient Complications and Conditions
• Allergies to Equipment and Supplies
– Adhesive allergy
• Place gauze square over site;
have patient remove in 15 minutes
• Or, have patient apply pressure
for 5 minutes instead of bandage
– Antiseptic allergy
• Use alternate antiseptic
– Latex allergy
• Look for sign indicating latex allergy on patient’s door
• Use nonlatex equipment (e.g., gloves, tourniquet, &
bandages)
Patients with known
allergies often wear
special armbands or
have allergy-specific
warning signs posted in
their hospital rooms.

(cont.)
• Excessive Bleeding
– Patients on aspirin or anticoagulant may bleed longer
– Maintain pressure until bleeding stops
– If bleeding continues >5 minutes, notify appropriate personnel
Never apply a pressure bandage instead of
maintaining pressure until bleeding has stopped, and
do not dismiss an outpatient or leave an inpatient until
bleeding has stopped or the appropriate personnel
have taken charge of the situation.

(cont.)
• Fainting
– A loss of consciousness
& postural tone
– Caused by insufficient
blood flow to brain
– Have patients w. history of
fainting lie down during
venipuncture

(cont.)
• Nausea and Vomiting
– Discontinue blood draw until feeling subsides
– Give patient emesis basin or wastebasket
– Apply cold, damp washcloth to forehead
• 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 if pain persists

(cont.)
• Petechiae
– Tiny, nonraised red spots
– Appear on arm when
tourniquet is applied
(Copyright Medical Training Solutions.
Used with permission.)

(cont.)
• Seizures/Convulsion
– 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 Risks
• Hematoma Formation
– Discontinue draw immediately & hold pressure over site 2
minutes
– Offer cold compress or ice pack if it is large & swollen
• Iatrogenic Anemia
– Anemia brought about by blood loss from blood draws
– Life is threatened if >10% of blood volume is removed at once
– Collect only minimum required specimen volumes
• Inadvertent Arterial Puncture
– Signs: rapidly forming hematoma, blood filling tube quickly

Procedural Error Risks (cont.)
• Infection
– Avoid by doing the following:
• Don’t open tape or bandages ahead of time
• Don’t preload needles onto tube holders ahead of time
• Don’t touch needle insertion site after sterilizing it
• Minimize time between needle cap removal & venipuncture
• Remind patient to keep bandage on at least 15 minutes

• Nerve Injury
– Caused by:
• Improper site or vein
selection
• Inserting needle too
deeply or quickly
• Excessive lateral
redirection of needle
• Blind probing
– If initial vein entry is unsuccessful:
• Use slight forward or backward redirection of needle
• Remove needle & try an alternate site
Abnormal hand position called “Claw
hand” caused by ulnar nerve injury

• Reflux of Anticoagulant
– Blood flows back into vein from collection tube
– Tube additives (e.g., EDTA) may cause adverse reaction
– Keep arm in downward position & tube below venipuncture site
• Vein Damage
– Avoid numerous venipunctures in the same area over time
– Avoid blind probing & improper technique
Match risks to procedural errors in the
WORKBOOK activity Matching 9-5.

Specimen Quality Concerns
• Hemoconcentration
– A decrease in fluid content of blood
– An increase in nonfilterable large molecules
– Caused by stagnation of normal venous flow due to tourniquet
• Hemolysis
– Damage to or destruction of RBCs
– Hemoglobin escapes into fluid part of specimen
• Partially Filled Tubes (short draw)
– Blood-to-additive ratio may be incorrect

Specimen Quality Concerns (cont.)
• Specimen Contamination
– Allowing alcohol residue, fingerprints, glove powder, baby
powder, urine on newborn screening samples
– Getting glove powder on blood films or capillary specimens
– Dripping perspiration into capillary specimens
– Following improper antiseptic procedure
– Using wrong antiseptic
• Wrong or Expired Collection Tube

Troubleshooting Failed Venipuncture
• 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
– Needle beside vein
– Undetermined position
Remember, to
troubleshoot failed
venipuncture the
important steps are:
STOP, ASSESS, &
CORRECT.

Needle Position
A: Correct needle position; blood can flow freely into the
needle.

Needle Position (cont.)
B: Needle not inserted far enough; needle does not enter
vein.

C: Needle bevel partially out of the skin; tube vacuum will
be lost.

D: Needle bevel partially into the vein; causes blood
leakage into tissue.

E: Needle bevel partially through the vein; causes blood
leakage into tissue.

F: Needle bevel completely through the vein; no blood flow
obtained.

G: Needle bevel against the upper vein wall prevents blood
flow.

H: Needle bevel against the lower vein wall prevents blood
flow.

I: Needle bevel penetrating a valve prevents blood flow.

J: Needle beside the vein; caused when a vein rolls to the
side.

K: Collapsed vein prevents blood flow despite correct
needle position.

Troubleshooting Failed Venipuncture
(cont.)
• Collapsed Vein
– Vein walls draw together temporarily, shutting off blood flow
– Caused by:
• Vacuum of tube or plunger pressure is too strong for vein
• Tourniquet is too tight or too close to site
• Tourniquet is removed during draw
(esp. w. elderly)
• Tube Vacuum
– Loss of vacuum due to bevel
partially out of skin
– Loss of vacuum due to damage
of tube
There are a lot of new terms
in this chapter. See how
many you can unscramble in
the WORKBOOK
Knowledge Drill 9-2
Scrambled Words activity.

NAACLS Entry Level Competencies Met in
This Chapter
• 4.4 List the general criteria for suitability of a specimen for
analysis, and reasons for specimen rejection or
recollection.
• 5.4 Describe substances that can interfere in clinical
analysis of blood constituents and ways in which the
phlebotomist can help to avoid these occurrences.
• 6.1 Identify potential sites for venipuncture and capillary
(dermal) puncture.
• 6.4 List the effects of tourniquet, hand squeezing, and
heating pads on specimens collected by venipuncture
and capillary (dermal) puncture.

NAACLS Entry Level Competencies Met in
This Chapter (cont.)
• 6.8 Explain the causes of phlebotomy complications.
• 6.9 Describe signs and symptoms of physical problems
that may occur during blood collection.
• 7.5 Identify and report potential preanalytical errors that
may occur during specimen collection, labeling,
transporting, and processing.

Questions?

Chapter 09 Preanalytical Considerations

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