Diagnostic Tests and Specimen Collection

Diagnostic Tests and Specimen Collection

Diagnostic Testing and the Nursing Process
Planning
Diagnostic Tests
Laboratory Tests
Hematology Tests

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


Chemistry Tests
* Whole blood, plasma, and serum
* Body fluids such as:
o Urine, spinal fluid, gastric contents
* Chemistry tests provide information about biochemical reactions such as electrolyte balances and organ function.
* Some institutions use automated computerized blood chemistry testing.
* Examples of tests available are:
o Serum albumin, alkaline phosphatase (ALP), aspartate aminotransferase (AST)
o Total bilirubin, serum calcium, cholesterol, glucose, LDH, phosphate, total protein, BUN, uric acid
Blood Glucose

* Blood glucose is a test commonly performed at the bedside or in the physician’s 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

Serology Tests

* Based on analysis of serum
* Used to diagnose both viral and bacterial diseases or determine antibody levels for:
o 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
* 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

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.

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
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

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

Ultrasonography

* Records the reflection of sound wave directed into the tissues
* Used to diagnose pathologic conditions of
o Uterus, ovaries, prostate, heart, liver, kidneys, pancreas, gallbladder, lymph nodes, thyroid, eyes, and peripheral blood vessels
* Often used in conjunction with nuclear medicine scans
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:
o Chest x-ray
o Barium swallow and upper GI series
o KUB (kidneys, ureters, and bladder)
o Gallbladder series

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

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
* 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.


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
o Abnormal blood in cardiac vessels can be detected as can valvular dysfunction.

* 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 patient’s leg may be immobilized for several hours.
* New angioseal devices may preclude the need for post procedure pressure.
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.
* 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.


Other Tests

* Endoscopic examinations of:
o The stomach (gastroscopy)
o The sigmoid colon (proctosigmoidoscopy)
o The entire colon (colonoscopy)
o The bladder (cystoscopy)
o The gallbladder and common bile duct (endoscopic retrograde cholangiopancreatograhy [ERCP])

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

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.

Diagnostic Tests and Specimen Collection.ppt