In many healthcare settings, the medical assistant is responsible for collecting blood specimens from patients and even performs some testing in the waived category. In order to properly collect the specimens, you will need to review the circulatory system and the function of blood. You will be introduced in this chapter to venipuncture and capillary collection procedures, and you will learn the appropriate supplies and equipment needed to perform these procedures.
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48
Collecting, Processing,
and Testing Blood
Specimens
Trang 2when collecting, processing, and testing blood samples
48.2 Carry out the procedure for collecting a blood
specimen
48.3 Discuss ways to respond to patients’ needs
when collecting blood.
48.4 Carry out the procedure for performing blood
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Introduction
• Medical assistant
– Collects blood specimens
– Performs waived testing
– Knowledge needed
• Dealing with patients
• How to obtain a blood sample
• Appropriate supplies and equipment
• How to perform and screen common blood tests
Trang 4• Phlebotomy
• Putting the patient at ease
• Processing specimens and
conduct testing
• Completing necessary
paperwork
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Apply Your Knowledge
What is the role of the medical assistant related to
collecting blood samples?
ANSWER: The medical assistant will put the
patient at ease during the procedure, process
specimens, conduct testing, complete necessary
paperwork, and make sure specimens are handled
properly.
Trang 6• Review the test order
• Assemble equipment and supplies
– Varies with test type
– Collection devices ~ label correctly
– Alcohol wipes; adhesive bandage
– Tourniquet for venipuncture
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Collecting Blood Specimens
• Preparing the patient
– Greet and identify the patient
– Confirm pretest preparation
– Explain the procedure and safety precautions
– Establish chain of custody
– Handle an exposure incident
Trang 8• Know your scope of practice for your state
• Phlebotomy
– Use Standard Precautions
– Use appropriate PPE
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Drawing Blood (cont.)
Trang 10• Needle and syringe
systems
• Butterfly system
– Winged infusion set
– Less trauma to vein
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Drawing Blood (cont.)
• Collection tubes
– Color-coded to identify appropriate
additive such as EDTA
– Be sure to select the
correct tubes – Draw in correct order
Trang 12• Engineered safety devices
– Reduce the possibility of needlestick injuries
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Drawing Blood (cont.)
• Capillary puncture
– Superficial puncture of the skin
– Sites ~ outer edge of finger or heel
• Lancet
• Automatic puncturing
device
Trang 14• Micropipettes
• MICROTAINER tubes
• Reagent products
• Smear slides
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Apply Your Knowledge
What precautions should you take when collecting
a blood specimen?
ANSWER: You should use Standard Precautions and
appropriate personal protective equipment.
Trang 16• Respond with sensitivity and competence
• Provide information appropriate to
patient’s needs
• Answer questions that are within your
scope of practice
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Patient Fears and Concerns
Trang 18• Patients at risk for uncontrolled bleeding
– Hemophilia or taking blood-thinning
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Special Considerations (cont.)
• Difficult patients
– Difficult venipuncture ~ do not stick more than
twice – Fainting patients ~ position to avoid injury
– Angry or violent
patient ~ do not argue
Trang 20ANSWER: After drawing blood on a patient taking
anticoagulants, you should hold a cotton ball over
the puncture site for at least 5 minutes, monitor the
site carefully, and notify the physician if bleeding
does not stop.
What is one precaution you can take when drawing
blood from a patient who is taking anticoagulants?
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Performing Common Blood Tests
• Results aid in diagnosis
• POLs – waived tests
• Be familiar with other tests also
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Trang 24• Complete blood (cell) count
– RBC count
– White blood cells
– Differential WBC
count
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Trang 26• Differential Cell count
– Prepare a smear slide and stain the smear
– Staining kits – Cell type / 100 leukocytes counted
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Hematologic Tests (cont.)
Trang 28• Hemoglobin
– Sample must undergo hemolysis
– Color then evaluated
– Automated hemoglobin analyzers
• Measure amount of hemoglobin in whole blood
• Follow manufacturer’s instructions
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Hematologic Tests (cont.)
• Cell morphology – requires special
training
• Coagulation tests
– PT and PTT
– Automated devices ~ calculate International
Normalized ratio (INR)
Trang 30• Erythrocyte sedimentation rate (ESR)
– Measures rate of RBCs falling to the bottom of the blood sample
– Tube must contain an
anticoagulant – Read after one hour
– Record as mm/hr.
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Chemical Tests
• Specialized equipment and techniques
• Subject to CLIA ‘88 regulations
• New automated equipment
– More readily available
– Simpler to operate
– Development of new waived tests
Trang 32• Blood glucose monitoring
– Routinely performed in POL
– Glucometer – Patient education
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Chemical Tests (cont.)
• Hemoglobin A1c
– Glucose molecules bind to hemoglobin
– Provides overall picture of effectiveness of
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– Enzyme-linked immunosorbent assay (ELISA)
– Immunofluorescent antibody (IFA) test
Trang 36• Rapid screening tests
– Detect antibodies to certain infections
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Apply Your Knowledge
Matching:
_ Lysing RBCs/evaluating the color B Serology test
_ Shape or form of objects C Coagulation tests _ Identify bleeding problems D Chemical test
_ Rate at which RBCs fall E Differential
_ Percentage of each type of WBC F Morphology
Trang 38process blood specimens for examination, make sure the test results are handled
efficiently and accurately, and complete the
necessary paperwork before and after each test
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• confirm the patient’s identity
• cleanse the skin prior to collection
• follow standard precautions
• collect the sample needed in the appropriate tube or container
• ensure the patient’s safety
Trang 40blood drawn Good communication by the medical assistant is the key to easing these fears
There are always patients who will have special needs Each patient will present a special set of challenges and should be treated with the utmost care and concern
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In Summary (cont.)
48.4 Hematologic, chemical, and serologic tests
require special care when performing them
The medical assistant should review the manufacturer’s instructions carefully for important information about correctly
performing each test
Trang 42Blood will tell, but often it
tells too much
~ Don Marquis