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CHAPTER 16 Specimen Handling, Transport, and Processing http://evolve.elsevier.com/Warekois/phlebotomy
2. Cold agglutinins and cryobrinogen samples
should be
a. chilled before collection.
b. transported on ice to the laboratory.
c. warmed before collection and
transported warmed.
d. transported at room temperature.
3. Infant bilirubins are transported
a. on ice.
b. in amber-colored microtubes.
c. in a heel-warmer packet.
d. without special transport measures.
4. Once a cap is removed from a blood tube,
the pH
a. may decrease.
b. may increase.
c. will not change.
d. becomes alkaline.
5. Which of the following can be centrifuged
immediately after collection?
a. Serum separator tubes
b. Clot tubes
c. Thrombin tubes
d. Sodium citrate tubes
6. Which of the following specimens would not
be rejected?
a. A CBC collected in a lithium heparin tube
b. An EDTA tube used for a chemistry test
c. A sodium level collected in a sodium
heparin tube
d. A cold agglutinin sample transported in
a heel-warmer packet
7. Complete blood clotting may take
___________ at room temperature.
a. 10 to 15 minutes
b. 20 to 30 minutes
c. 30 to 45 minutes
d. 1 hour
8. The major risk of stopper removal is
a. glycolysis.
b. hemolysis.
c. aerosol.
d. clotting.
9. Which of the following is used to identify a
patient specimen in the laboratory?
a. Name of the collector of the specimen
b. Accession number
c. Specimen type
d. Name of the person depositing specimen
in the laboratory
Copyright 2016, 2011, 2007, 2002 by Saunders, an imprint of Elsevier Inc. All rights reserved.
CHAPTER 17 Point-of-Care Testing
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243
oint-of-care testing is the performance of analytic
P
tests at the “point of care,” which may be at the
bedside, in the clinic, or even in the patient’s home.
Tests are done with small portable instruments that
offer signicant time and cost savings in many situations. Blood tests typically performed at the point of
OU TL I NE
Advantages of Point-of-Care
Testing
Common Tests Performed at
the Point of Care
Hematology
Coagulation
Chemistry
Procedure 17-1: Ancillary
Blood Glucose Test
Electrocardiography
The Cardiac Cycle
Electrocardiogram Equipment
Performing an Electrocardio-
gram
Other CLIA-Waived Tests
Occult Blood
Urinalysis
Pregnancy
OB J E CT IV E S
After completing this chapter, you should be able to:
1. Define point-of-care testing (POCT), and explain its
advantages and disadvantages.
2. Discuss the importance of quality-assurance activities
in POCT.
3. Describe the testing principle and clinical usefulness
of the following:
a. Activated coagulation time
b. Blood gases and electrolytes
c. Cardiac troponin T
d. Cholesterol
care include many tests in hematology, coagulation,
and chemistry. In addition, the multiskilled phlebotomist may perform electrocardiography, occult blood
analysis, urinalysis, pregnancy testing, and multiple
tests for infectious diseases, including rapid group A
Streptococcus (“strep”) and HIV.
Infectious Disease
Rapid Group A Streptococcus
Respiratory Syncytial Virus
Influenza A and B
Helicobacter pylori
Human Immunodeficiency Vi-
rus
Review for Certification
e. Dipstick urinalysis
f. Glucose
g. Hemoglobin
h. Occult blood
i. Pregnancy testing
j. Prothrombin time
4. Perform the ancillary blood glucose test.
5. Describe the major features of an electrocardiogram
and outline important points of patient preparation.
KE Y TE R M S
alternate site testing (AST)
ancillary blood glucose test
cardiac cycle
cardiac troponin T
(cardiac TnT)
conduction system
Copyright 2016, 2011, 2007, 2002 by Saunders, an imprint of Elsevier Inc. All rights reserved.
depolarization
electrocardiogram
(ECG or EKG)
electrocardiography
point-of-care testing
(POCT)
P wave
Q-T interval
rapid group A
Streptococcus
repolarization
sinoatrial node
ST segment
stylus
T wave
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CHAPTER 17 Point-of-Care Testing http://evolve.elsevier.com/Warekois/phlebotomy
AB BR E VI AT IO NS
ABGs arterial blood gases
ACT
activated coagulation time
APTT
activated partial thromboplastin time
AST
alternate site testing
BNP
B-type natriuretic peptide
CHD
congestive heart disease
CLIA ‘88
Clinical Laboratory Improvement Act of 1988
COPD
chronic obstructive pulmonary disease
EBV
Epstein-Barr virus
ECG, EKG
EDTA
FDA
g/dL
electrocardiogram
ethylenediaminetetraacetic acid
Food and Drug Administration
grams per deciliter
Hb hemoglobin
hCG
human chorionic gonadotropin
Hct
hematocrit
HIV
human immunodeficiency virus
NP
nasopharyngeal
POC
point of care
POCT
point-of-care testing
PT
prothrombin time
RBCs
red blood cells
RSV
Respiratory syncytial virus
TnT
troponin T
WBCs
white blood cells
ADVANTAGES OF POINT-OF-CARE
TESTING
Point-of-care testing (POCT) refers to the perfor-
mance of analytic tests immediately after obtaining a
sample, often in the same room that the patient is seen
in (the “point of care”). POCT is also known as alter-
nate site testing (AST). POCT may be performed at the
bedside, in the intensive care unit or emergency room,
or in outpatient settings such as a clinic, physician’s of-
ce, nursing home, assisted living center, or the patient’s
own home. Box 17-1 lists special considerations to keep
in mind when drawing blood at a patient’s home.
The advantages of POCT are considerable. By
“bringing the laboratory to the patient,” the turnaround
time for obtaining test results is shortened, allowing
more prompt medical attention, faster diagnosis and
treatment, and potentially decreased recovery time.
BOX 17-1 Reminders for Performing
Phlebotomy in a Patient’s Home
1. When obtaining the specimen, always have the patient
sitting or reclining in a safe, comfortable chair or bed.
2. Be aware of the nearest bathroom or sink. Carry antiseptic
towelettes for handwashing.
3. Carry a cell phone for emergencies.
4. Always bring biohazard containers for specimen transport
and removal of sharps.
5. Make sure that the patient has completely stopped bleeding
before leaving.
6. Recheck the phlebotomy area to ensure that all materials
used during the procedure have been removed and
disposed of properly.
7. Preserve the specimen for transport at the proper
temperature.
Most tests performed as POCT are tests waived by the
Clinical Laboratory Improvement Act of 1988 (CLIA
’88). Such tests are called “CLIA waived.” The Food
and Drug Administration (FDA) decides which tests
are CLIA waived based on the ease of performing and
interpreting the test. A CLIA-waived test is not subject
to regulatory oversight by government authorities. The
FDA website maintains a complete list of waived tests.
An essential feature of a CLIA-waived test is
that the testing equipment and procedure are so
simple and accurate that erroneous results are unlikely. Results are read directly from digital displays
or monitors on the instrument. Although the direct
cost per test is often more with these instruments,
the total cost to the laboratory is often less when the
time and cost for sample delivery or after-hours
stafng of the laboratory are considered.
As the health care delivery landscape changes,
and as more versatile and sophisticated devices are
developed, POC testing is likely to become even
more widespread and is likely to be used for more
tests and in more settings. Becoming familiar with
the newest POCT products will help you maintain
an advantage in a changing health care system.
FLASHBACK
You learned about CLIA ‘88 in Chapter 2.
Tests such as bleeding times have always been done
at the bedside. The signicant expansion of POCT in
recent years has been possible because of the development of miniaturized analytic equipment and microcomputers. Instruments used in POCT are small, portable, and often handheld, with some tests requiring no
instruments, only a card or reagent strip or “dipstick.”
Copyright 2016, 2011, 2007, 2002 by Saunders, an imprint of Elsevier Inc. All rights reserved.
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245
In general, POCT instruments are easy to use, the required training is simple, and they can be used by a
variety of medical professionals, including phlebotomists, nurses, nurse assistants, and physicians.
Although these instruments are easy to use, the
importance of carefully following the manufacturer’s
instructions cannot be overemphasized. For example,
some manufacturers follow the traditional method of
wiping away the rst drop of blood from a dermal
puncture and using subsequent drops for testing.
However, a few instrument makers use the rst drop
of blood for their procedures. Using the second drop
with such instruments would give false readings.
Quality assurance and controls are still essential for
the use of POCT instruments, just as they are with
laboratory based instrumentation. The laboratory is
usually responsible for documentation and maintenance of POCT instruments. Finally, proper and adequate training for all personnel performing these procedures is critical to implement POCT successfully.
Strict adherence to guidelines regarding calibrating
equipment, running controls, performing maintenance,
and keeping records is a must for a POCT program.
Failure in any one of these areas can lead to erroneous
test results and negative consequences for patients.
COMMON TESTS PERFORMED
AT THE POINT OF CARE
Here we discuss some of the most common point-ofcare tests likely to be performed by the phlebotomist.
A more complete list is given in Box 17-2.
Hematology
Hemoglobin (Hgb) is the most common hematology test performed as a POC test. Hemoglobin
testing is used to diagnose and monitor anemia.
A simple, fast method of anemia testing uses a
handheld hemoglobin analyzer (Figure 17-1). Such
instruments can use arterial, venous, or dermal
blood specimens and typically give readouts in less
than a minute. A whole blood sample is placed into
a microcuvette or on a test strip, which is then
inserted into the machine for a reading. The instrument determines the hemoglobin value in grams
per deciliter (g/dL), which can be tracked over the
disease course or be used to determine the response
to therapy. Instruments are also available that
provide readings of red blood cells (RBCs), white
blood cells (WBCs), and platelets.
A hematocrit (Hct) reading is sometimes made
at the bedside or, more commonly, in the clinic
ofce. Blood is collected into a microhematocrit
tube and spun down quickly using a tabletop centrifuge. Results are available within 2 minutes.
Coagulation
Coagulation monitoring is used to monitor patients
with clotting disorders who are receiving therapy.
Several handheld instruments are used for bedside
measurement. Some use only a single drop of whole
blood obtained from a dermal puncture; others use
citrated blood obtained by venipuncture. Most give
results in 5 minutes or less.
Heparin therapy may be monitored by determining the activated coagulation time (ACT). A small
volume of blood is collected in a prewarmed tube
that contains a coagulation activator. The tube is
incubated at 37° C for 1 minute and then inspected
by tilting the tube to determine whether a clot is
present. If not, the tube is inspected every 5 seconds
thereafter, with incubation continuing between observations. An automated ACT tester is available
BOX 17-2 Point-of-Care Tests
• B-type natriuretic peptide (BNP)
• Cardiac troponin T (TnT)
• Cholesterol
• Coagulation testing (ACT, PT, and APTT)
• Electrocardiography
• Glucose
• Hemoglobin
• Multiple chemistry panels (arterial blood gases, electro-
lytes, and blood urea nitrogen)
Copyright 2016, 2011, 2007, 2002 by Saunders, an imprint of Elsevier Inc. All rights reserved.
FIGURE 17-1 Handheld instruments such as the i-STAT system
can perform chemistry analysis quickly and accurately. The test
cards shown are for a chem 8 panel (basic metabolic panel), cTnI
(troponin) and G3+ (blood gasses-pH, PCO
, and PO2).
2
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CHAPTER 17 Point-of-Care Testing http://evolve.elsevier.com/Warekois/phlebotomy
as well. The activated partial thromboplastin time
(APTT) can also be used to monitor heparin therapy. With recent advances in POCT instrumentation, physicians now have a choice of tests for
monitoring heparin therapy (Figure 17-2). Oral
anticoagulant therapy using warfarin (Coumadin)
is monitored by the prothrombin time (PT) test.
CLIA-waived PT testing instruments are frequently
used in physicians’ ofces and clinics (Figure 17-3).
Antiplatelet medications, which are used to prevent stroke, and include aspirin and clopidogrel,
may also require monitoring for their effect on
coagulation.
Chemistry
Glucose
Bedside glucose monitoring is the most common
chemistry test done by POCT. Glucose is determined with dermal puncture and reagent strips. The
specimen tested is whole blood.
Ancillary Blood Glucose Test
The ancillary blood glucose test is performed at the
bedside, most often for patients with diabetes mellitus. Steps for this test are shown in Procedure 17-1.
Blood collected by dermal puncture is applied to a
paper reagent strip or a microcuvette, depending on
the instrument. Because different manufacturers
have somewhat different procedures for their machines and test strips, be sure to read and understand
the directions for the one you are using. Before any
FIGURE 17-3 The ProTime Microcoagulation System for pro-
thrombin time testing is designed to safely manage warfarin
(Coumadin) therapy. (Courtesy ITC, Edison, N.J.)
patient sample can be tested, the instrument must be
calibrated with materials provided by the manufacturer. This is usually performed by laboratory personnel at scheduled times. Control solutions must
also be run using the same procedure as for the patient’s test. These results are recorded as well. If any
values fall outside the ranges provided by the manufacturer, troubleshooting must be performed until
the values are correct. Proper calibration and control
are critical for accurate results. Be sure to follow
your institution’s instructions exactly regarding performance and frequency.
FIGURE 17-2 The Hemochron system is designed to manage the
effects of anticoagulation drugs such as heparin. (Courtesy ITC,
Edison, N.J.)
Hemoglobin A1C
Hemoglobin A1c can be analyzed as a CLIA-waived
test, using a handheld portable testing monitor. It
can be used at the bedside or other POC, providing
immediate results. An example of a CLIA-waived
device is the CHEK Diagnostics A1C now MultiTest A1c System. These devices are designed for
clinics and physicians’ ofces to manage patients
with diabetes. The test monitors the long-term effectiveness of diabetes therapy by providing a reading of A1c, a protein related to the average blood
glucose level over a period of 4 to 6 weeks.
Cardiac Troponin T
Cardiac troponin T (cardiac TnT) is part of a protein
complex in cardiac muscle that aids the interaction of
actin and myosin. Damaged cardiac muscle releases
Copyright 2016, 2011, 2007, 2002 by Saunders, an imprint of Elsevier Inc. All rights reserved.
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PROCEDURE 17-1
Ancillary Blood Glucose Test
1. Perform a routine capillary collection
(presented in Procedure 10-1).
Some manufacturers do not recommend wiping
away the rst drop of blood. Check the insert
for the product you are using.
2. Collect the sample.
Collect the blood drop directly onto the strip.
Cover the appropriate area on the stick with a
free-falling drop of blood. Be careful not to
touch the strip yourself or allow the patient’s
skin to touch it because this can contaminate
the strip.
247
3. Read and record the result.
Values that are well outside the range of normal
(called “panic” values) should be reported
immediately to the nursing staff or the
physician in charge. Your laboratory should
have a policy regarding the exact values that
trigger such notication.
Copyright 2016, 2011, 2007, 2002 by Saunders, an imprint of Elsevier Inc. All rights reserved.
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cardiac TnT, and the plasma level of cardiac TnT
rises within 4 hours after an acute myocardial infarction (heart attack). It may stay elevated for up to
2 weeks, and its level may help determine the extent
of damage and the patient’s prognosis. Therefore
monitoring cardiac TnT can provide valuable information for a patient with a possible myocardial
infarction. Bedside determination is performed
using anticoagulated whole blood, and results are
available within 15 minutes (Figure 17-4).
Lipids
Cholesterol levels may be determined as part of a
routine examination or to monitor therapy with
cholesterol-lowering drugs. Some POCT determinations use a one-step, disposable color card test
rather than a machine. These use whole blood from
either a dermal puncture or a heparinized venous
sample. Blood is applied to a card, and a color
determination is made after the reaction takes place.
Other cholesterol POCT methods use instrumentation (see Figure 17-1).
Blood Gases and Electrolytes
Several instruments are available that can analyze
arterial blood gases (the concentrations of oxygen
and carbon dioxide and the pH) and common electrolytes (sodium, potassium, calcium, chloride, and
bicarbonate). Some systems are small enough to be
handheld; others require a cart. They are particularly
useful when frequent or rapid chemistry determinations must be made, such as in the emergency room
or intensive care unit. Because of their complexity,
all these instruments require careful calibration and
more training than do simpler instruments such as
hemoglobin analyzers. The specimen tested is whole
blood.
B-Type Natriuretic Peptide
B-type natriuretic peptide (BNP), also known
as brain natriuretic peptide, is a hormone made by
the heart in response to expansion of ventricular
volume and pressure overload. Its production
increases in patients with congestive heart disease
(CHD). The measurement of BNP at the bedside
allows the practitioner to quickly differentiate
between chronic obstructive pulmonary disease
(COPD) and CHD, which may have similar symptoms. BNP can also be monitored to determine
the effectiveness of CHD therapy. The BNP test
requires a whole blood sample collected in ethylenediaminetetraacetic acid (EDTA).
ELECTROCARDIOGRAPHY
Electrocardiography is a method for recording the
electrical activity of the heart. The output of the
electrocardiograph is a tracing, called an electro-
cardiogram (ECG or EKG). The ECG is used to
diagnose heart disease such as ischemia, myocardial
infarction, or brillation.
With the increasing demand for multiskilled
personnel, developing the ability to perform electrocardiography is a natural progression for phlebotomists. It is beyond the scope of this chapter to
give a complete introduction to this topic. Instead,
we give the broad outlines needed to understand
electrocardiography and present the basics of
patient preparation and ECG recording.
FIGURE 17-4 The Cardiac Reader system allows rapid determi-
nation of the cardiac markers troponin T and myoglobin from a
single whole blood sample. (Courtesy Roche Diagnostics, Indianapolis, Ind.)
The Cardiac Cycle
As you learned in Chapter 7, each heartbeat cycle
includes a contraction and relaxation of each of the
four chambers of the heart. This contraction is triggered and coordinated by electrical impulses from
the heart’s pacemaker, called the sinoatrial node,
located in the upper wall of the right atrium. Electrical impulses spread out from there through the
heart’s conduction system, triggering the coordinated contraction of the heart muscle. The cardiac
cycle refers to one complete heartbeat, consisting of
depolarization (contraction) and repolarization
(recovery and relaxation) of both the atria and the
ventricles. The electrical activity occurring during
this cycle is recorded on the ECG.
The normal ECG consists of a tracing with ve
prominent points where the graph changes direction.
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ischemia may be associated with elongation of
the Q-T interval, and myocardial injury may cause
elevation of the ST segment above its normal position. The duration of the cardiac cycle can be read
directly from the ECG because each small square
represents a known unit of time (Figure 17-6).
249
P
Q S
Atrial
depolarization
Ventricular
depolarization
FIGURE 17-5 ECG tracing depicting P, Q, R, S, and T cycles.
(Modified from Flynn JC, Jr: Procedures in phlebotomy, ed. 3,
Philadelphia, 2005, Saunders.)
T
Ventricular
repolarization
These are arbitrarily known as P, Q, R, S, and
T (Figure 17-5). The regions immediately surrounding each point are known as the P wave, T wave,
and so on. As shown in the gure, the sections
joining these points are known variously as segments, complexes, or intervals. Each part of the
graph corresponds to a particular portion of the cardiac cycle and can be analyzed to determine how the
heart is functioning (Table 17-1).
Important parameters that can be determined
from the ECG include the time intervals between
different phases of the cardiac cycle, which indicate
conduction efciency, and the size of the electrical
signals, which may be correlated with an increase
or decrease of heart muscle mass. For instance,
Electrocardiogram Equipment
The electrical activity of the heart is recorded with
10 numbered electrodes that are placed in dened
locations on the patient’s chest, arms, and legs
(Figure 17-7). The electrodes may be applied with
an electrolyte solution to increase conductivity.
A wire, is attached to each electrode. The wires
pass to the ECG machine through a cable. The tracing is made on heat- and pressure-sensitive paper
by a stylus.
Performing an Electrocardiogram
The machine and the patient should be positioned
away from electrical equipment, including televisions, air conditioners, and other functioning appliances. The patient should be wearing a gown
that opens in the front, and the lower legs must be
exposed. The patient should be lying down and must
remain still during the ECG (Figure 17-8). Electrode
locations are cleaned with alcohol and shaved of
hair, if necessary. Disposable adhesive electrodes are
available, or electrolyte cream or gel is applied if reusable electrodes are being used. Electrodes are applied to the proper locations (as outlined in Box 17-3)
and secured in place. The machine is turned on, and
the recording is made. Many ECG machines automatically cycle through the 10 electrodes; alternatively, the technician switches the machine by hand
to record from each electrode for a short time. After
successfully recording from each electrode, the electrodes are removed, the skin is cleaned, and the patient
can get dressed.
TABLE 17-1 Electrocardiogram Measurements
ECG Section Heart Activity
P wave Atrial depolarization
P-R interval Time between atrial contraction and
QRS complex Ventricular depolarization
ST segment Time between ventricular depolarization
T wave Ventricular repolarization
Q-T interval Time between ventricular depolarization
Copyright 2016, 2011, 2007, 2002 by Saunders, an imprint of Elsevier Inc. All rights reserved.
ventricular contraction
and beginning of repolarization
and completion of repolarization
FIGURE 17-6 Analyzing an ECG tracing.
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A B
FIGURE 17-7 ECG electrodes are attached to the chest (A) and to the right and left legs (B), as well as to the arms.
FIGURE 17-8 Patient and equipment position during an ECG.
BOX 17-3 Placement of Chest Electrodes
V1, fourth intercostal space to the right of the sternum
V
, fourth intercostal space to the left of the sternum
2
V
, midway between position 2 and position 4
3
V
, fifth intercostal space at the left midclavicular line
4
V
, fifth intercostal space at the left anterior axillary line
5
V
, fifth intercostal space at the left midaxillary line
6
OTHER CLIA-WAIVED TESTS
The number of CLIA-waived tests is growing because of both advances in bioanalytic chemistry and
recognition that such tests allow more exible delivery of care by a wider range of staff. The following tests are commonly performed as CLIA-waived
tests, though not necessarily at the bedside or with
handheld instruments.
Occult Blood
The occult blood test uses a card kit or slide and is
a guaiac-based test. The stool specimen is placed
on the card (two windows) or slide, and the reagent
or developer solution (stabilized peroxide reagent)
is added to the test area (Figure 17-9). Detection of
occult blood in feces is used in the diagnosis of
digestive tract diseases such as gastric ulcers or
colon cancer. The patient must be informed of dietary restrictions that need to be followed before
the test.
Urinalysis
Many commonly requested urine tests can be
performed using a dipstick, a plastic strip with
reagents embedded in it. Tests may include pH,
protein, glucose, ketones, bilirubin, urobilinogen,
blood, leukocyte esterase, nitrite, and specic gravity. Before testing begins, the urine specimen must
be at room temperature and thoroughly mixed. The
urine strip is briey and completely immersed in a
well-mixed fresh urine specimen (Figure 17-10).
After removal, excess urine is blotted from the side
of the strip (Figure 17-11). The color change on the
strip is compared with the reference color chart on
the bottle at the appropriate time (Figure 17-12).
The change may be read by eye or with a tabletop
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251
FIGURE 17-9 Applying developer to the occult blood card.
FIGURE 17-10 In a routine urinalysis procedure, the strip is
completely immersed in the urine and then evaluated against the
control, usually found in the bottle.
FIGURE 17-11 Remove excess urine by withdrawing the strip
along the side of the container.
FIGURE 17-12 Compare the color change on the strip with the
chart on the bottle.
instrument that reads the strip. The microscopic
component of a urinalysis examination is NOT a
waived test and must be performed by a qualied
health care practitioner such as medical laboratory
scientist (MLS) or medical laboratory technologist
(MLT). MLS, MT, or MLT.
Copyright 2016, 2011, 2007, 2002 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Pregnancy
A pregnancy test detects the presence of human
chorionic gonadotropin (hCG), a hormone produced
by the placenta after implantation of a fertilized
egg. This hormone is present in both urine and serum, and test kits are available for each.
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