chapter © 2011 the mcgraw-hill companies, inc. all rights reserved. 48 collecting, processing, and...

CHAPTER

© 2011 The McGraw-Hill Companies, Inc. All rights reserved.

48Collecting,

Processing, and Testing Blood

Specimens


48-2

Learning Outcomes

48.1 Discuss the composition and function of blood.

48.2 Describe the process for collecting a blood specimen.

48.3 Explain the importance of confirming patients’ identities and correctly identifying blood samples.

48.4 Describe how to perform venipuncture and capillary puncture procedures.


48-3

Learning Outcomes (cont.)

48.5 Identify the equipment and supplies required for blood-drawing procedures.

48.6 Discuss the correct procedures for disposing of waste generated during blood-drawing procedures.

48.7 Discuss common fears and concerns of patients and how to ease these fears.


48-4

Learning Outcomes (cont.)

48.8 Develop techniques for helping patients with special needs, including children, the elderly, patients at risk for uncontrolled bleeding, and difficult patients.

48.9 Identify common blood tests and explain their purposes.

48.10Perform certain blood tests.


48-5

Introduction

• Medical assistant– Collects blood specimens

– Performs waived testing

– Knowledge needed• Understand circulatory system and function of

blood• Appropriate supplies and equipment• How to perform and screen common blood tests


48-6

Role of the Medical Assistant

• Phlebotomy – insertion of a needle or cannula into a vein to withdraw blood

• Put the patient at ease during procedure

• Process specimens and conduct testing

• Complete necessary paperwork and make sure specimens are handled properly


48-7

Functions and Composition of Blood

• Circulatory system transports blood– Heart pumps 8–12 pints of blood

through 70,000 miles of vessels/day

• Hematology – the study of blood


48-8

Functions and Composition of Blood (cont.)

• Functions of blood

– Distributes oxygen, nutrients, and hormones

– Eliminates waste products

– Attacks infecting pathogens

– Maintains acid-base balance

– Regulates body temperature


48-9


• Red blood cells – erythrocytes – Internal respiration

– Transport oxygen to cells• Hemoglobin – 98%• Dissolved in plasma – 2 to 3 %

– Hemoglobin • Main component of RBCs• Protein containing iron


48-10


• White blood cells – leukocytes– Protect against infection– Granular

• Basophils• Eosinophils• Neutrophils

– Agranular• T and B lymphocytes• monocytes


48-11


• Platelets – thrombocytes – Fragments of

cytoplasm

– Essential for clot formation

• Plasma – Clear, yellow liquid

– Contains formed elements of blood

– 90% water

• Serum – clear, yellow liquid remaining after clot formation


48-12


• Blood types or groups– Presence of antigens A and B

determines type

– Blood also carries antibodies

• Transfusions require careful matching to prevent hemolysis


48-13

Apply Your Knowledge

1. 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.


48-14


ANSWER: Functions of the blood are: (list any 3)

1. Distributes oxygen, nutrients, and hormones

2. Eliminates waste products3. Attacks infecting pathogens4. Maintains acid-base balance5. Regulates body temperature

2. What are three functions of blood?


48-15

Collecting Blood Specimens• Reading and

interpreting the test order

– Review order

– Assemble equipment and supplies

• Preparing the patient

– Greet and identify the patient

– Confirm pretest preparation

– Explain the procedure and safety precautions

– Establish chain of custody


48-16

Collecting Blood Specimens (cont.)

• Use Standard Precautions and PPE as needed

• Handling exposure incident– Needlestick or other exposure to blood/blood

products– Report to appropriate person immediately– Wash area and apply bandage– Document date, time, people involved, type of

exposure


48-17

Drawing Blood

• Not all states permit medical assistants to draw blood

• Venipuncture – Puncture of a vein– Most common sites

are in the antecubital fossa and forearm

Common Sites for Venipuncture


48-18


• Venipuncture complications– Hematoma

• Hold needle still• Hold pressure on site

after removal of needle

– Latex allergy• Ask patient• Use non-latex gloves,

tourniquet, and bandages

– Nerve injury• Know anatomy

– Infections • Rare• Clean site prior to

venipuncture• May not be evident for

several days


48-19


• Equipment– Evacuation systems – use special double-

pointed needle, needle holder

– Needle and syringe systems

– Butterfly system – winged infusion set and syringe

– Collection tubes • Sealed to create a vacuum• Color-coded to identify appropriate additive


48-20


• Engineered safety devices– Reduce the possibility of needlestick

injuries

– Types • Retracting needles• Hinged or sliding shields• Self-blunting needles• Retractable lancets


48-21


– Reagent products –chemically treated paper or dipstick

– Smear slides

• Capillary puncture– Superficial puncture of

skin with sharp point

– Lancets – small, disposable instruments

– Automatic puncturing devices

– Micropipettes – small, calibrated glass tubes that hold a precise volume of fluid


48-22


What precautions should you take when collecting a blood specimen?

ANSWER: You should use Standard Precautions and appropriate personal protective equipment.


48-23

Responding to Patient Needs

• Respond with sensitivity and competence

• Fears and concerns – Pain

– Bruises or scars

– Serious diagnosis

– Contracting a disease from the procedure


48-24

Special Considerations

• Children– Talk with parent or caregiver first

– Address child directly

– Speak in a calm, soothing voice

– Explain the procedure briefly in terms they can understand

– Keep child informed of status during the procedure


48-25

Special Considerations (cont.)

• Elderly– Prone to bruising

– Difficult to obtain an adequate sample

– Speak clearly in a low-pitched voice

– Allow adequate time for patient to respond to questions


48-26


• Risk of bleeding– Hemophilia or taking blood-thinning

medication

– Hold site for at least 5 minutes

– Contact physician if bleeding does not stop


48-27

– Angry or violent patients

• Explain need for testing

• Avoid arguing• Do not force patient• Document behavior

and if patient refuses


• Difficult patients– Difficult

venipuncture – do not stick more than twice

– Fainting patients –• Reaction to blood

draw• Position to avoid

injury

• Difficult patients– Difficult

venipuncture – do not stick more than twice

– Fainting patients –• Reaction to blood

draw• Position to avoid

injury


48-28


ANSWER: 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?

Correct!


48-29

Performing Common Blood Tests

• Results aid in diagnosis

• POLs often only perform waived tests

• Know office policy


48-30

Performing Common Blood Tests (cont.)

• Chemicals in lab– Anticoagulants – keep blood in uncoagulated

state

– Serum separators – form a gel-like barrier between serum and clot in coagulated sample

– Stains – color particular cells


48-31

Hematologic Tests

• Blood counts– RBC count

– White blood cells

– Differential white blood cell

– Platelet

– Hematocrit

– Hemoglobin Centrifuged Capillary Sample


48-32

Hematologic Tests (cont.)

• Morphologic studies– Morphology – study of shape and form of

objects – Requires special training

• Coagulation tests– Identification of potential bleeding problems– Monitor therapeutic drug levels for

anticoagulants– PT and PTT


48-33

Hematologic Tests (cont.)

• Erythrocyte sedimentation rate

– Measures rate of RBCs falling to the bottom of

the blood sample

– Must be performed on a fresh sample

– Tube must contain an anticoagulant

– Read after one hour

– Recorded as mm/hr


48-34

Chemical Tests

• Rarely performed in the POL

• Waived tests

– Blood glucose monitoring

– Hemoglobin A1c

– Cholesterol tests


48-35

Serologic Tests• Introduction of an antigen

or antibody into a specimen and detection of a reaction to it

• Immunoassays – Western blot– Radioimmunoassay

(RIA)– Enzyme-linked

immunosorbent assay (ELISA)

– Immunofluorescent antibody (IFA) test

• Rapid screening tests– Infectious mononucleosis– HIV– Helicobacter pylori


48-36


Matching:

___ Hemoglobin A1c A. ESR

___ 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

___ ELISA G. Hemoglobin

ANSWER:

G

F

E

D

C

B

A

Super!


48-37

In Summary

48.1 Blood is composed of plasma (the liquid portion) and formed elements. Blood serves as a transport medium for oxygen, nutrients, hormones, and waste products and also attacks infecting organisms, maintains acid-base balance, and regulates body temperature.

48.2 Blood is collected by one of two means: venipuncture or capillary puncture. Venipuncture is the process of obtaining a blood sample from a vein, and capillary puncture is the process of obtaining blood from a superficial skin puncture.


48-38

In Summary (cont.)

48.3 It is essential that a patient’s identity be confirmed before a blood sample is collected. Correctly identifying the blood sample with the patient’s name ensures that the correct test will be done for the correct patient.

48.4 Venipuncture is performed by cleansing the skin in the antecubital space, applying a tourniquet above the space, inserting a needle into the vein in the space, and withdrawing blood by way of an evacuated tube. Capillary puncture involves cleansing the skin on the finger, sticking the finger with a safety lancet, and applying the drop of blood to a slide or in a small tube.


48-39

In Summary (cont.)

48.5 The supplies needed to perform a venipuncture include VACUTAINER components (safety needle, needle holder/adapter, collection tubes), antiseptic and cotton balls or antiseptic wipes, tourniquet, sterile gauze squares, and sterile adhesive bandages. Capillary puncture requires capillary puncture device (a safety lancet or an automatic puncture device such as Autolet or Glucolet), antiseptic and cotton balls or antiseptic wipes, sterile gauze squares, sterile adhesive bandages, reagent strips, micropipettes, and smear slides.


48-40

In Summary (cont.)

48.6 All waste generated during blood-drawing procedures should be disposed of immediately. Sharps should be placed in the sharps container after activating the safety device, and gloves, gauze, and other disposable supplies should be placed in a biohazard container.

48.7 Patients are often concerned about pain, bruising, and scarring when having blood drawn. They are sometimes afraid that they may have a serious disease, especially if large amounts of blood are drawn. Good communication by the medical assistant is the key to easing these fears.


48-41

In Summary (cont.)

48.8 There are always patients who will have special needs, including children, the elderly, patients who have bleeding disorders, and difficult patients. Each patient will present a special set of challenges and should be treated with the utmost care and concern.

48.9 The most common tests performed in a physician’s office laboratory include hematologic tests, chemical tests, and serologic tests.


48-42

In Summary (cont.)

48.10 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.


48-43

End of Chapter 48

Blood will tell, but often it tells

too much.

~ Don Marquis

chapter © 2011 the mcgraw-hill companies, inc. all rights reserved. 48 collecting, processing, and...

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