CHAPTER 24 Diagnostic Tests and Specimen Collection

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CHAPTER 24 Diagnostic Tests and Specimen
Collection
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CHAPTER 24 THEORY OBJECTIVES

• CORRECTLY USE THE TERMS LISTED FOR THIS CHAPTER.
• DESCRIBE EACH OF THE SEVEN CATEGORIES OF TESTS
  THAT ARE COMMONLY PERFORMED.
• DISCUSS APPROPRIATE PSYCHOSOCIAL CARE TEACHING
  FOR PATIENTS UNDERGOING DIAGNOSTIC TESTS OR
  PROCEDURES.
• EXPLAIN FACTORS TO BE CONSIDERED WHEN AN OLDER
  ADULT IS TO UNDERGO DIAGNOSTIC TESTING.
• PREPARE TO PERFORM A CAPILLARY BLOOD GLUCOSE
  TEST, A VENIPUNCTURE, A THROAT CULTURE, A
  URINE DIPSTICK AND STOOL FOR OCCULT BLOOD TEST.

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Diagnostic Testing and the Nursing Process

• When diagnostic tests are ordered, the nurse
  should
• Assess the patient and establish the patients
  knowledge levels.
• Determine any nursing procedures required to
  protect the safety of the patient.
• Assess for patient allergies to iodine
• Nursing diagnosis will relate to Knowledge,
  Deficient, related to
• (Contd)

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Diagnostic Testing and the Nursing Process

• (Contd)
• Planning
• Verify that items needed for preparation are on
  hand.
• Check to see that pretest medications are on the
  unit or available.
• Prepare to do patient teaching.
• Prepare for preprocedure treatments such as
  enemas or IV starts.

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Diagnostic Tests

• Provide information about chemical reactions
  affecting physiologic functioning of the body
• Enable examination of blood, urine, and other
  body fluids, which provides clues about the
  functioning of various organs, body systems, and
  mechanisms
• Used to confirm diagnosis and guide treatment
• Provide information concerning changes in a
  patients condition

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Laboratory Tests

• Hematology Tests
• Complete blood count (CBC)
• Information about the state of health or presence
  of illness
• Number of red blood cells (erythrocytes)
• Type and number of white blood cells
  (differential)
• Platelet count, PT, PTT, INR
• (Contd)

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Laboratory Tests

• (Contd)
• During infection, the number and type of white
  blood cells increase.
• Neutrophil counts can be significant.
• In severe infections, bone marrow releases more
  granulocytes.
• Immature polymorphonuclear neutrophils are
  released (called bands).
• The result is a shift to the left (more bands).
• (Contd)

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Laboratory Tests

• (Contd)
• Drug therapy may cause leukopenia (a decrease in
  leukocytes).
• Hemoglobin shows the capacity of the blood to
  transport oxygen from the lungs to the tissues.
• A normal platelet count is essential to clotting.
• Coumadin therapy is guided by prothrombin time
  (reported in INR numbers).
• The erythrocyte sedimentation rate (ESR) gives
  clues about inflammatory conditions.

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Chemistry Tests

• Chemistry tests are performed on
• Whole blood, plasma, and serum
• Body fluids such as
• Urine, spinal fluid, gastric contents
• Chemistry tests provide information about
  biochemical reactions such as electrolyte
  balances and organ function.
• (Contd)

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Chemistry Tests

• (Contd)
• Some institutions use automated computerized
  blood chemistry testing.
• Examples of tests available are
• Serum albumin, alkaline phosphatase (ALP),
  aspartate aminotransferase (AST)
• Total bilirubin, serum calcium, cholesterol,
  glucose, LDH, phosphate, total protein, BUN, uric
  acid

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Blood Glucose

• Blood glucose is a test commonly performed at the
  bedside or in the physicians office by the
  nurse.
• Guides insulin therapy for diabetics
• Guidelines for performing test depend on
  manufacturer of testing equipment
• Requires a finger stick to obtain capillary blood
• Review Skill 24-2

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Serology Tests

• Based on analysis of serum
• Used to diagnose both viral and bacterial
  diseases or determine antibody levels for
• Dysentery, rheumatic fever, typhoid, influenza,
  rubella, and syphilis
• Can also be used to determine titers in response
  to vaccines
• May use radionuclides such as iodine-125 and
  iodine-131
• (Contd)

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Serology Tests

• (Contd)
• Examples of serology tests ordered
• Agglutination test for specific organisms
• Antistreptolysin-O titer
• Blood typing ABO groups and Rh
• Carcinoembryonic antigen assay (CEA)
• Coombs test
• C-reactive protein antiserum
• Heterophil antibody titer
• Tests for syphillis

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Urinalysis

• Provides information about kidney function or
  other body functions and diseases
• Single, catheterized, or random specimens can be
  collected anytime, with no special preparation.
  First voided specimen is preferred.
• Urine deteriorates quickly and should be tested
  soon after collection.
• (Contd)

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Urinalysis

• (Contd)
• Midstream collections
• External genitalia are cleansed
• A small amount of urine is passed.
• Urine is collected from midvoiding in a sterile
  container.
• Used for cultures when a bladder infection is
  suspected
• (Contd)

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Urinalysis

• (Contd)
• Timed, long-period specimens
• Collected over 12- or 24-hour period
• Container may be kept on ice and has some form of
  preservative.
• Used to determine kidney function and possible
  glomerulonephritis or acute tubular necrosis

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Other Laboratory Tests

• Bacteriology
• Histology
• Cytology
• Ova and parasites
• Cultures from specimens of feces, blood, urine,
  wound drainage, or samples of body tissue or
  fluids

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Ultrasonography

• Records the reflection of sound wave directed
  into the tissues
• Used to diagnose pathologic conditions of
• Uterus, ovaries, prostate, heart, liver, kidneys,
  pancreas, gallbladder, lymph nodes, thyroid,
  eyes, and peripheral blood vessels
• Often used in conjunction with nuclear medicine
  scans

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Radiology Procedures

• Most common test is radiation by x-ray
• Produces images in varying densities on film
  after it passes through the body
• Commonly performed radiology procedures
• Chest x-ray
• Barium swallow and upper GI series
• KUB (kidneys, ureters, and bladder)
• Gallbladder series
• (Contd)

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Radiology Procedures

• (Contd)
• IVP (intravenous pyelogram)
• X-ray of bony skeleton
• Arthrogram
• Myelogram
• Radionuclide scan
• Computed tomography (CT) scan

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Magnetic Resonance Imaging

• Noninvasive method of differentiating body tissue
  (commonly used for brain, knee joint, spine and
  spinal cord, and abdominal organs)
• Requires that all metal be removed from the
  patient
• Contraindicated in patients with hip prostheses,
  implanted pacemakers or defibrillators,
  artificial cardiac valves, or vascular clips or
  staples from recent surgery
• (Contd)

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Magnetic Resonance Imaging

• (Contd)
• Patient teaching is very important before this
  procedure patient needs to know the duration of
  the test and that it requires being in a noisy
  environment.
• Patient may become claustrophobic during test.
• Patient needs to know deep-breathing and
  relaxation techniques.

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Cardiopulmonary Studies

• EKG/ECG
• Diagnoses heart rhythms and heart disease
  measures electrical activity of the heart
• Cardiac catheterization
• An invasive procedure used to determine function
  of heart valves, coronary artery blood flow, and
  oxygenation at different points in the heart and
  to diagnose coronary artery disease
• Abnormal blood in cardiac vessels can be detected
  as can valvular dysfunction.
• (Contd)

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Cardiopulmonary Studies

• (Contd)
• Surgical procedure that requires consent
• Procedure is performed under sterile technique in
  radiology or a surgical suite.
• Postprocedure requires checking insertion site
  every 10 to 15 minutes for possible bleeding.
• If the femoral approach is used, the patients
  leg may be immobilized for several hours.
• New angioseal devices may preclude the need for
  post procedure pressure.
• (Contd)

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Cardiopulmonary Studies

• (Contd)
• Treadmill Stress Test
• A cardiac-monitored ECG test
• Patient is on a treadmill, which is used to
  increase heart rate and blood pressure with
  controlled activity.
• Test may be done with radioisotope imaging
• Patient should avoid smoking, dairy products, or
  drinking caffeine for 4 hours before the test.
• (Contd)

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Cardiopulmonary Studies

• (Contd)
• Angiography/Arteriography
• Used to locate lesions, occluded vessels, tumors,
  and malformed blood vessels
• A contrast medium is injected during the
  procedure (check for allergies).
• Consent is required.
• Patient should be NPO for at least 6 hours before
  the test.
• Patient may be given preprocedure sedation.

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Other Tests

• Endoscopic examinations of
• The stomach (gastroscopy)
• The sigmoid colon (proctosigmoidoscopy)
• The entire colon (colonoscopy)
• The bladder (cystoscopy)
• The gallbladder and common bile duct (endoscopic
  retrograde cholangiopancreatograhy ERCP)
• (Contd)

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Other Tests

• (Contd)
• Electroencephalography (EEG)
• Measures neurologic and physiologic activities of
  the brain via the electrical discharges from the
  brain
• Performed to localize and diagnose brain lesions,
  scars, epilepsy, infections, or clots
• Performed to determine brain death in comatose
  patients on life support

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Things to Remember

• All invasive tests requiring injection of a
  medium require a consent.
• Tests requiring premedication or sedation usually
  require a consent.
• Many tests have some form of preparation review
  the laboratory manual for your facility to
  determine what must be done before the patient
  has the test and after the patient has had the
  test.