Chapter 29

Diagnostic Testing

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Noninvasive and Invasive Testing

Noninvasive means the body is not entered with any type of instrument.

Invasive means accessing the body’s tissue, organ, or cavity through some type of instrumentation procedure.

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Preparing the Client for Diagnostic Testing

Appropriate test selection Correct scheduling Confirming client’s normal baseline vital

signs Evaluating client’s knowledge of

procedure

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Preparing the Client for Diagnostic Testing (continued)

Reporting significant information to practitioner• Allergies, previous adverse reactions

Documentation of significant data Client teaching about the procedure Interventions

• NPO status• Medication administration

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Care of the Client During Diagnostic Testing

Standard precautions or aseptic technique Preparation of the room Ongoing assessment of the client’s status Gathering and charging for supplies Testing the equipment to ensure it is

functioning and safe Proper containers for specimen collection Management of procedural pain

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Care of the Client During Diagnostic Testing

Nursing assessment and interventions are based on the nature of the test and whether or not anesthesia was administered.

The client is monitored for respiratory distress, bleeding.

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Care of the Client During Diagnostic Testing

The client receives written discharge instructions.

Clients may need to have follow-up appointments made for them.

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Laboratory Tests

Detect and quantify the risk of future disease Establish and exclude diagnoses Assess the severity of the disease process and

determine the prognosis Guide the selection of interventions Monitor the progress of the disorder Monitor the effectiveness of the treatment

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Laboratory Tests

The clinical value of a test is related to:• Sensitivity• Specificity• Incidence• Predictive value

Test results are based on normal range values.

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Specimen Collection

Venipuncture Arterial Puncture Capillary Puncture Central Lines Implanted Port

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Specimen Collection

Urine Collection• Random collection• Timed collection• Collection from a closed drainage system• Clean-voided specimen

Stool Collection

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Hematologic System

Red Blood Cells (erythrocytes) White Blood Cells (leukocytes) Platelets

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Hematologic System

Red Cell Indices• Measure the size and hemoglobin content of

the RBCs- Mean Corpuscular Volume (MCV)- Mean Corpuscular Hemoglobin (MCH)- Mean Corpuscular Hemoglobin Concentration

(MCHC)

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Hematologic System

Platelets• Maintain hemostasis and blood coagulation• Blood coagulation is a comprehensive,

sequential process of the body’s response to injury.

• Prothrombin activator is the governing element in blood coagulation.

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Platelets

Platelet Count, Size, and Shape Bleeding Time Prothrombin Time (PT) Partial Thromboplastin (PTT) Fibrinogen Level Thrombin Time (TT)

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Hematologic System

Sickle Cell Test (hemoglobin S)• Sickle cell trait• Sickle cell disease

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Hematologic System

Blood Type• A. B, AB, O• Determined by the presence or absence of A

or B antigens.• Rh factor refers to an antigen found on the

RBC.

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Hematologic System

Blood Crossmatching• Determines the compatibility of the donor’s

blood with that of the recipient

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Hematologic System

Erythroctye Sedimentation Rate (ESR)• Rate with which the RBCs settle in

saline/plasma over a specified time period• Diagnostic for inflammatory and chronic

conditions

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Blood Chemistry

Blood Chemistry Analyses • Sequential multiple analyzer (SMA) • Performs 4 to 20 biochemical tests • Ordered separately or as profile groups

(SMA panels)- SMA-4- SMA-6- SMA-12- SMA-20

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Blood Chemistry

• Blood Glucose• Serum Electrolytes• Blood Enzymes• Blood Lipids• Therapeutic Drug Monitoring• Arterial Blood Gases

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Blood Chemistry

Blood Glucose• Deficits in either the digestion of

carbohydrates or glucose metabolism• Drugs can cause elevated blood glucose

values. • Clients receiving intravenous fluids with a

high glucose content

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Blood Chemistry

Serum Electrolytes• An element or compound that, when

dissolved, separates into ions and provides for cellular reactions

- Cations- Anions

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Blood Chemistry

Blood Enzymes• Catalyze chemical reactions within the cells

by promoting oxidative reactions and synthesis of various chemicals

- Lipids- Glycogen- Adenosine triphosphate (ATP)

• Key role in diagnosing degree of tissue damage when released into blood

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Blood Chemistry

Blood Lipids• Total blood cholesterol• Lipoproteins are blood lipids bound to

proteins that transport cholesterol and other fats to and from the cells.

- Low-density lipoprotein (LDL)- High-density lipoprotein (HDL)

• Triglycerides are the chemical form in which most fat exists in food and in the body.

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Therapeutic Drug Monitoring

Performed when a quantitative relationship exists between the drug concentration and drug response or toxicity is known.

Trough and peak sampling help keep the drug level below toxic value.

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Blood Chemistry

Arterial Blood Gases (ABG)• PO2• PCO2• pH

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Urine Tests

Urinalysis (UA) is essential for both diagnostic and preventive purposes.• Urine pH• Specific gravity• Urine glucose• Urine ketones• Urine cells and casts

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Stool Tests

Stool analysis is used to determine the various constituents of the stool for diagnostic purposes such as diseases of the gastrointestinal tract, the liver, and the pancreas.• Urobilinogen• Occult blood• Parasites

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Culture and Sensitivity Tests

Culture refers to the growing of microorganisms to identify the pathogen.

Sensitivity allows the practitioner to select the appropriate antibiotic therapy.

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Culture and Sensitivity Tests

Blood Culture Swab (throat) Culture Sputum Culture Urine Culture Stool Culture Wound Culture Bone Marrow

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Papanicolaou Test (Pap Smear)

Evaluates the cell maturity, metabolic activity, and morphologic variations of the cervical tissue

Papanicolaou testing can also be used for tissue specimens from other organs, such as bronchial aspirations and gastric secretions.

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Papanicolaou Test (Pap Smear)

Cervical pap smear testing is recommended every 2 to 3 years after the onset of sexual activity.

Annual testing is indicated for women:• Over 40 years of age• With a family history of cervical cancer• With a previously positive test

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Radiologic Studies

Radiography is the study of X-rays or gamma ray-exposed film and is used to study internal organ structure.

Fluoroscopy is used to demonstrate the motion of organs when used with contrast medium.

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Radiologic Studies

Contrast Media• Radiopaque substances that facilitate

roentnen imaging of the internal structures- Barium- Iodine

• Clients with a history of allergies to any foods or drugs (particularly fish or iodine) may be predisposed to allergic reactions to contrast media.

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Radiologic Studies

Chest X-ray Kidney-Ureter-Bladder (KUB) Mammography Skeletal X-rays Computed Tomography (CT)

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Computed Tomography (CT)

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Barium Studies

Barium is a chalky, white contrast medium.

Allow for visualization of the internal structures of the digestive tract.

Fluids are forced to help with excretion. If not completely excreted, barium can

cause an intestinal obstruction.

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Barium Studies

Barium Swallow (esophography)• Upper gastrointestinal study (UGI) • Fluoroscopic visualization of the esophagus

Barium Enema (rectal infusion of barium sulfate• Roentgenographic study of the lower

intestinal tract

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Angiography

Visualization of the vascular structures through the use of fluoroscopy with a contrast medium

Reveals blood flow to heart, lungs, brain, kidneys, and lower extremities

Useful in diagnosing an aneurysm

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Angiography

Arteriography Cardiac Catheterization Digital Subtraction Angiography Lymphangiography Venography

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Dye Injection Studies

Iodine is a common dye used in radiographic studies.

May cause temporary symptoms of shortness of breath, nausea, and a warm, hot-flushed sensation.

Most dye injection studies are invasive, requiring written consent.

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Cholangiography

The roentgenographic procedure visualizing the integrity of the biliary system by a radiopaque contrast medium• Intravenous Cholangiography• Percutaneous Cholangiography• T-Tube Cholangiography

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Oral Cholecystography

Visualization of the gall-bladder and presence of stones

Administration of radiopaque iodine tablets

The evening before the test the client eats a fatty meal and takes the iodine tablets 5 minutes apart with 8 ounces of water.

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Cystography

Radiographic study that uses an aqueous iodine contrast agent instilled into the bladder through a urinary catheter

Used to visualize the bladder, urethra, ureteral openings

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Intravenous Pyelogram (IVP)

A series of x-ray films of the kidneys, ureters, and bladder

An intravenous iodine preparation is administered.

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Bronchography

Radiographic study of the trachea and bronchi

A contrast agent is injected through a catheter.

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Myelography

Study of the spinal cord and its surrounding subarachnoid spaces through the use of radiography and Pantopaque (contrast agent)

The Pantopaque dye is injected by performing a lumbar puncture.

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Ultrasonography

Ultrasound (echogram) is a noninvasive study that uses high-frequency sound waves to visualize deep body structures.

A transducer emits waves that travel through the body tissue and are reflected back to the transducer and recorded.

The varying density of body tissues deflects the waves into a differentiated pattern on an oscilloscope.

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Ultrasonography

Brain Thyroid Heart Vascular Structure Abdominal Aorta

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Ultrasonography

Spleen Liver Gallbladder Pancreas Pelvis

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Ultrasonography

Echocardiogram Doppler Ultrasonography

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Magnetic Resonance Imaging (MRI)

Noninvasive procedure that places the client in a magnetic field instead of ionizing radiation

Provides contrast between normal tissue and pathologic tissue

Evaluates lesions and changes in the body’s organs, tissues, vascular, and skeletal structures

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Radioactive Studies

Use radionuclides (nuclear scanning) to image the morphologic and functional changes in the body’s structure

Reveal congenital abnormalities, lesions, skeletal changes, infections, gland, and organ enlargement

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Electrodiagnostic Studies

These diagnostic tests use devices to measure the electrical activity of the heart, brain, and skeletal muscles.• Electrocardiography• Signal-Averaged Electrocardiography• Stress Test• Thallium Test • Electroencephalography

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Endoscopy

Visualization of a body organ or cavity through a scope

A light at the end of the scope allows the practitioner to assess for lesions and structural problems.

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Aspiration/Biopsy

Aspiration is performed to withdraw fluid that has abnormally collected, or to obtain a specimen.

A tissue biopsy (excision of a small amount of tissue) can be obtained during aspiration or with other diagnostic tests.

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Aspiration/Biopsy

Amniocentesis• Withdrawal of amniotic fluid to obtain a

sample for specimen examination

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Bone Marrow Aspiration/Biopsy

Common sites are the sternum and iliac crest.

A fluid specimen (aspiration) or a core of marrow cells (biopsy) is obtained.

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Paracentesis

Aspriation of fluid from the abdominal cavity

Diagnostic or therapeutic A trocar (a large-bored abdominal

paracentesis needle) is advanced into the peritoneal cavity.

An inner catheter drains the fluid.

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Thoracentesis

Aspiration of fluids from the pleural cavity The client is monitored for symptoms of a

pneumothorax (collection of air or gas in the pleural space causing the lungs to collapse).

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Cerebrospinal Fluid (CSF) Aspiration

Lumbar puncture (spinal tap) is the aspiration of CSF from the subarachnoid space.• To obtain a pressure measurement when

blockage is suspected• During a myelogram• To instill anesthesia, antibiotics, or

chemotherapy

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Lumbar Puncture