Diagnostic Tests

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Diagnostic Tests

• SHUROUQ QADOSE

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• Diagnostic and laboratory Tests
• Are tools that provide information about the
  client, also run to find the cause of disease or
  discomfort tests used to make a diagnosis.
• Purpose of diagnostic tests
• Help to confirm a diagnosis
• Monitor an illness
• Provide valuable information about the clients
  response to treatment

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• Diagnostic testing involves three phases-
•   Pretest
• The major focus of the pretest phase is client
  preparation
• The nurse must know what equipment and supplies
  are needed for the specific test
• What type of sample will be needed and how it
  will be collected?
• Does the client need to stop oral intake for a
  certain number of hours prior to the test?

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• Does the test include administration of contrast
  media and if so, it is injected or swallowed?
• Are medications given or withheld?
• Is consent form required?
• How long is the test?

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• Intratest
• It focuses on specimen collection and performing
  or assisting with certain diagnostic testing.
• The nurses uses of special standard precautions
  and sterile techniques
• Provide emotional and physical support while
  monitoring the client as needed (e.g., V /S,
  pulse oximetry, ECG).
• Correct labeling, storage, and transportation of
  the specimen to avoid invalid test results.

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• Post test
• The focus of this phase is on nursing care of the
  client and follow up activities and
  observations.
• Compare the previous and current test results
• Modify nursing interventions as needed
• Report the results to appropriate health team
  members.

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• Blood Tests
•  Complete Blood Count (CBC) which includes-
• Hemoglobin
• Hgb test is a measure of the total amount of
  hemoglobin in the blood
• Hematocrit
• Hct measures the percentage of red blood cells in
  the total blood volume

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• RBC count
• The number of RBC per cubic millimeter (mm3) of
  whole blood
• WBC or leukocyte
• The number of circulating WBC per cubic
  millimeter of whole blood
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• Serum Electrolytes
• Ordered as a screening test for electrolyte and
  acid base imbalance.
• The most commonly ordered serum tests are for
  sodium, potassium, chloride , and bicarbonate
• Evaluate renal function Urea, Creatinine
• Urea, the end product of protein metabolism is
  measured as BUN. Creatinine is produced in
  relatively constant quantities by the muscles and
  is excreted by the kidneys.
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• Serum Osmolality
• Serum Osmolality is a measure of the solute
  concentration of the blood. The particles
  included are sodium ions, glucose, and urea.
• It is estimated by doubling the serum sodium
• Serum Osmolality values are used to evaluate
  fluid balance
• Normal values are 280-300 mOsm/kg.
• An increase in Osmolality indicates a fluid
  volume deficit

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• Drug monitoring
• Is conducted when the client is taking a
  medication with narrow therapeutic range such as
  digoxin.
• This includes monitoring drawing blood samples
  for peak and trough levels to determine if the
  blood serum levels of a specific drug are at a
  therapeutic level and not a sub therapeutic or
  toxic level.
• Peak level the highest concentration of the drug
  in the blood serum
• Trough level lowest concentration

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• Arterial Blood Gases ABGs
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• Take specimen of the ABG from the radial,
  Brachial, femoral arteries.
• Need to apply pressure to the puncture side for
  about 5-10 minutes after removing the needle.
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• Blood Chemistry
• Certain enzymes such as Lactic dehydrogenase
  LDH, Creatine Kinase CK , serum glucose,
  hormones such as thyroid hormone, cholesterol and
  triglycerides.
• A common test is the glycosylate hemoglobin
  HbA1C, which is a measurement of blood glucose
  that is bound to hemoglobin. HbA1C is reflection
  of how well blood glucose levels have been
  controlled during the prior 3 to 4 months.

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• Capillary Blood Glucose
•  
• Measure blood glucose when frequent tests are
  required or a veinpuncture cannot be performed.
• Less painful, easily performed

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• Specimen Collection
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• Nurses always assume the responsibility for
  specimen collection depending on the type of
  specimen and skill required.
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• Nursing responsibilities with specimen collection
• Explain the purpose of specimen collection and
  the procedure for obtaining the specimen.
• Provide client comfort, privacy, and safety.
• Use the correct procedure for obtaining the
  specimen collection.
• Note relevant information on the laboratory
  requisition slip such as medication the client is
  taking that may affect the results.
• Transport the specimen to the laboratory promptly
  to have more correct results.
• Report abnormal results to the health care
  provider

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• Stool Specimens
• Reasons for testing feces include the following
• To determine the presence of occult blood hidden
  blood. This test is referred to as the guaiac
  test.
• To analyze for dietary products and digestive
  secretions. An excessive amount of fat in the
  stool (steatorrhea) can indicate faulty
  absorption of fat from the small intestine.
  Decreased amount of bile in stool indicate
  obstruction in bile flow from liver and
  gallbladder to the intestine.

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• To detect the presence of ova and parasites. When
  collecting specimen for parasites, it is
  important to send the specimen as soon as
  possible while it is still warm.
• To detect the presence of bacteria or viruses, so
  the container must be sterile and aseptic
  technique in collection.

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• Collecting Stool Specimens
•  Before obtaining the specimen, the nurse must
  determine the reason for the collecting the stool
  specimen and the correct method of obtaining and
  handling.
•  Nurse need to give the clients the following
  instructions
• Defecate in a clean bedpan or bedside commode.
• Do not contaminate the specimen by urine or
  menstrual discharge.
• Do not place toilet tissues in the bedpan after
  defecation.
• Notify the nurse as soon as possible after
  defecation to send the specimen as soon as
  possible.
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• When obtaining the specimen the nurse should-
• Follow medical aseptic technique meticulously.
• Wear disposable gloves to prevent hand
  contamination and take care not to contaminate
  the outside of the specimen container.
• Use one or two clean tongue blades to transfer
  the specimen to the container.
• The amount of stool to be sent depends on the
  purpose for which the specimen is collected.

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• Label the specimen and the laboratory requisition
  have the correct information on them.
• Sends the specimen to the laboratory immediately.
• Document all relevant information, date, time of
  collection and all nursing assessments color,
  odor, consistency and amount of feces.

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• Testing Feces for Occult Blood
• Use of chemical reagent substance to detect the
  presence of the enzyme peroxidase in the
  hemoglobin molecule.
• A blue color indicates a guaiac positive result,
  that is, the presence of occult blood. No color
  change or any color other than blue is a negative
  finding, indicating the absence of blood in the
  stool.

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• Certain foods, medications, and vitamin C can
  produce incorrect test results.
• False positive results can occur if the client
  has recently ingested (a) red meat (b) raw
  vegetables or fruits, (c) certain medications
  that irritate the gastric mucosa and cause
  bleeding such as aspirin, NSAID, anticoagulants.
• False negative results can occur if the client
  has taken more than 250mgper day of vitamin C up
  to 3 days before the test even if bleeding is
  present.

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Positive guaiac test shown on right, as would be
seen for this patient. Negative result (on left)
included for comparison.
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• Urine Specimens
• The nurse is responsible for collecting urine
  specimens for a number of tests Clean voided
  specimens for routine urinalysis, clean catch
  or midstream urine specimens for urine culture,
  timed urine specimen, indwelling catheter
  specimen.

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• Clean voided Urine Specimen
• Usually done on the first voided specimen in the
  morning
• At least 10 ml of urine sufficient for routine
  analysis
• Client who is disabled, seriously ill or
  disoriented may need to use a bedpan or urinal in
  bed, these need special instructions
• The specimen must be free of fecal
  contamination
• Dont discard the toilet tissue in bedpan
• Put the lid tightly on the container to prevent
  spillage of the urine.
• If the outside of container is contaminated,
  clean it with a disinfectant.

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• The nurse must-
• Make sure that the specimen label with laboratory
  requisition carry the correct information and
  
  attach them securely to the specimen.
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• Clean-Catch or Midstream Urine Specimen
• It is collected when a urine culture is
  ordered to identify microorganisms causing
  urinary tract infection. Care is taken to ensure
  that the specimen is as free as possible from
  contamination around the urinary meatus.
• Clean catch specimens are collected into a
  sterile specimen container with a lid.
• Clean the urinary meatus with antiseptic solution
• Instruct the client to start voiding
• Collect 30-60 ml of urine in the container.
• Label the specimen and transport it to the
  laboratory.

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• Timed Urine Specimen
• It requires collection of all urine produced and
  voided over a specific period of time, ranging
  from 1-2 hours to -24 hours. Each voiding of
  urine is collected in a small, clean container
  and then emptied immediately into the large
  refrigerated bottle or carton.

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• It is done for the following purposes
• To assess the ability of the kidney to
  concentrate and dilute urine.
• To determine disorders of glucose metabolism such
  as DM.
• To determine levels of specific constitutes such
  as albumin, creatinine.

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• To collect the time urine specimen
• Obtain the specimen with preservative from the
  laboratory. Label the container with identifying
  information for the client, the test to be
  performed, time started, and time of completion.
• Provide a clean receptacle to collect urine
  (bedpan).
• Post signs in the clients chart, room, alerting
  the person to save all urine during the specified
  time.
• At the start of the collection period, discard
  the first voiding
• Save all urine produced during the time
  collection period in the container.
• At the end of collection, ask the pt to void the
  last time and add them in the container.
• Record collection of the specimen, timed started
  and completed.
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• Urine Testing
•  Several simple urine tests are often done by
  nurses on the nursing units. These include tests
  for specific gravity, PH, and the presence of
  abnormal constituent such as glucose, ketones,
  protein.
• Specific gravity is indicator of urine
  concentration, or the amount of solutes present
  in the urine
• Normally ranges from 1.010 to 1.025
• PH is measured to determine the relative acidity
  or alkalinity of urine (7 is neutral, less than 7
  is acidic, greater than 7 is alkaline).

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• Glucose urine is tested for glucose to screen
  clients for diabetes mellitus and to assess
  clients for abnormal glucose to tolerance during
  pregnancy.
• Ketones ketones bodies a product of the
  breakdown of fatty acids normally are not present
  in the urine.
• Protein
• Occult blood
• Osmolality is measure of the solute
  concentration of urine. Normal values are 500 to
  800 mOsm/kg.

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• Sputum specimen
• Sputum is the mucous secretion from the
  lungs, bronchi, and trachea.
• A sputum trap is used when the specimen is
  obtained by suctioning.
•  Sputum collection for the following purposes
• For culture and sensitivity to identify a
  specific microorganisms
• For cytology to identify the origin, structure,
  function and pathology of cells.
• For acid-fast bacillus for TB.
• To assess the effectiveness of therapy.
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• Throat Culture
• A throat culture sample is collected from the
  mucosa of the oropharynx and tonsillar regions
  using a culture swab.
• Obtaining a throat culture is an invasive
  procedure that requires the application of
  scientific knowledge and potential problem
  solving to ensure client safety.

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Visualization Procedures

• It includes indirect visualization (noninvasive)
  and direct visualization (invasive) techniques
  for visualizing body organ and system function.
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• Clients with Gastro intestinal Alteration
• Direct visualization techniques include
• Anoscopy viewing of the anal canal
• Proctoscopy viewing of the rectum
• Proctosigmoidoscopy viewing the rectum and
  sigmoid colon
• Colonoscopy viewing of the large intestine.

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• Indirect visualization of the gastrointestinal
  tract is achieved by
• X-rays of gastrointestinal tract can detect
  structure, obstructions, tumors, ulcers,
  inflammatory diseases or other structural changes
  such as hiatal hernias. Visualization of the
  tract is enhanced by the use of a barium. For
  examination of the upper gastrointestinal tract
  or small bowel, the client drinks the barium
  sulfate (barium swallow). For examination of the
  lower gastrointestinal tract, the client is given
  an enema containing the barium (Barium enema).

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Barium Swallow
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Upper endoscopy
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• Clients with Urinary Alterations
•  Visualization procedures also may be used to
  evaluate urinary function.
• An X ray of the KUB Kidneys, Ureters, Bladder
• IVP (Intravenous pyelography) contrast medium
  is injected intravenously.
• Retrograde pyelography contrast medium is
  instilled directly into the kidney pelvis via the
  urethra, bladder, and ureters following injection
  or instillation of the contrast medium, x- ray
  are taken to evaluate urinary tract structures.
• Ultrasonography noninvasive test that uses
  reflected sound waves to visualize the kidney.
• Cystoscopy a lighted instrument inserted through
  the urethra to visualize the bladder, urethral
  orifices
  and urethra.

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• Clients with cardio pulmonary Alterations
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• ECG Electrocardiography, recording of the
  hearts electrical activity.
• Electrocardiogram Detect arrhythmias and
  alteration in conduction indicative of myocardial
  damage, enlargement of the heart, or drug
  effects.

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• Stress electrocardiography Assess the clients
  response to an increased cardiac workload during
  exercise.
• Angiography invasive procedure requiring
  informed consent of the client. A radiopaque dye
  is injected into the vessels to be examined.
  Using x-rays the flow through the vessels is
  assessed and areas of narrowing or blockage can
  be observed.
• Echocardiogram noninvasive test that uses ultra
  sound to visualize structures of the heart and
  evaluate left ventricular function.

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• Lung scan
• Also known as V/Q (Ventilation / perfusion) scan,
  records emissions from radioisotopes that
  indicate how well gas and blood are traveling
  through the lungs.
• Laryngoscopy and bronchoscopy are sterile
  procedure. Tissue samples may also be taken for
  biopsy.

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• Computed Tomography (CT) or (CAT)
• Painless, noninvasive x-ray procedure that
  has the unique capabilities of distinguishing
  minor differences in the density of tissues.
  It produce a three dimensional image of the
  organ or structure.

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• Magnetic Resonance Imaging (MRI)
• Is a noninvasive diagnostic scanning
  technique in which the client is placed in a
  magnatic field. MRI provides a better contrast
  between normal and abnormal tissue than the CT
  scan. For visualization of the brain, spine,
  limbs, and joints, heart, blood vessels, abdomen
  and pelvis. The procedure lasts between 60 and 90
  minutes.
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• Aspiration/Biopsy
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• Aspiration withdrawal of fluid that has
  abnormally collected such as pleural cavity,
  abdominal cavity.
• Biopsy removal and examination of tissues.
  Usually performed to determine a diagnosis or to
  detect
  
  malignancy. Both
  aspiration and biopsy it needs sterile
  techniques.
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• Determine if the facility requires a signed
  informed- consent from the aspiration / biopsy
  procedures
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• Lumbar Puncture
• In lumbar puncture LP CSF is withdrawn through
  a needle inserted into the subarachnoid space of
  the spinal canal between the third and fourth
  lumbar vertebrae or between the fourth and fifth
  lumbar vertebrae.

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• Abdominal Paracentesis
• Normally the body creates just enough peritoneal
  fluid for lubrication. The fluid is continuously
  formed and absorbed into the lymphatic system.
• Ascites large amount of fluid accumulates in the
  abdominal cavity.

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• Abdominal Paracentesis carried out to obtain a
  fluid specimen for laboratory study and to
  relieve pressure on the abdominal organs due to
  the presence of excess fluid. A common site for
  abdominal Paracentesis is the midway between the
  umbilicus and the symphysis pubis on the midline.
  Normally about 1,500 ml is the maximum amount of
  fluid drained at one time to avoid Hypovolemic
  shock.

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• Thoracentesis
• Normally, only sufficient fluid to lubricate the
  pleura is present in the pleural cavity. However,
  excessive fluid can be accumulating as a result
  of injury, infection, or other pathology. It is
  performed to remove the excess fluid or air to
  ease breathing. Also it is performed to introduce
  chemotherapeutic drugs intrapleurally.

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• This is usually a sitting position with the arms
  above the head, which spreads the ribs and
  enlarges the intercostals space. Or in which the
  client leans forward over a pillow.
• A site on the lower posterior chest is often used
  to remove fluid, and a site on the upper anterior
  chest is used to remove air.

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• Bone Marrow biopsy
• Biopsies are performed on many different
  types of tissues such as bone marrow, liver,
  breast, lymph nodes and lungs. The bones of the
  body commonly used for a bone marrow biopsy are
  the sternum, iliac crests, anterior or posterior
  iliac crest spines, and proximal tibia in
  children. The posterior superior iliac crest is
  the preferred site with the client placed prone
  or on the side. 1-2 ml of bone marrow was
  withdraw.
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• Liver biopsy
• It is performed at the clients bedside, in
  which a sample of liver tissue is aspirated. A
  physician inserted a needle in the intercostals
  space between two of the right lower ribs and
  into the liver or through the abdomen below the
  right the right rib cage. The nurse applies
  pressure to the site to prevent bleeding, often
  by positioning the client on the biopsy site.

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