Diagnostic Testing

• diagnostics/laboratory test 


  tools that provide information about the client
• Diagnostic and Laboratory Tests


  Tests may be used for basic screening as part of a wellness check.
• primary role of the nurse in laboratory testing


  to teach the client and family or significant other how to prepare for the test and the care that may be required following the test.
• Nurses must also know the implications of the test results in order to provide the most appropriate nursing care for the client
• Diagnostic testing involves three phases

  pretest, intratest, and post-test.
• Instruct the client and family about the procedure for the diagnostic testing ordered
• Explain the purpose of the test.
• Instruct the client and family about activity restrictions related to testing
• Instruct the client and family on the reaction the

  diagnostic test may produce
• Provide the client with detailed information about the diagnostic testing equipment.
• Inform the client and family of the time frame for when the results will be available
• Instruct the client and family to ask any questions so that the health care provider can clarify information and allay any fears.
• blood test


  valuable information about the hematologic system and many other body systems
• venipuncture


  puncture of a vein for collection of a blood specimen
• phlebotomist


  person from a laboratory who performs venipuncture; collects the blood specimen for the tests ordered by the primary care provider
• complete blood count (CBC)


  basic screening test and one of the most frequently ordered blood tests
• complete blood count (CBC)


  specimens of venous blood
• complete blood count (CBC)

  = hemoglobin and hematocrit measurements = erythrocyte (RBC)count = leukocyte (wbc) count = red blood cell indices = differential white cell count
• red blood cell count

  number of rbc's per cubic milimeter
• red blood cell count (normal findings;adult)

  men: 4.6-6.0 million women: 4.0-5.0 million
• hemoglobin


  composed of a pigment (heme), which contains iron and a protein (globin)
• hemoglobin (normal findings; adult)

  men: 13.5-18 g/dl women: 12-15 g/dl
• hemoglobin ; anemia

  hemoglobin level falls below 10.5 g/dl
• hematocrit


  packed cell volume; fast way to determine the percentage of RBC's in the plasma - reported as a percentage because it is the proportion of RBC's to the plasma
• hematocrit (normal findings; adult)

  men: 40-54% women: 36-46%
• RBC indices ; mean corpuscular volume (MCV)

  mean or average size of the individual RBC
• RBC indices ; mean corpuscular hemoglobin (MCH)

  amount of hemoglobin present in one cell
• RBC indices ; mean corpuscular hemoglobin (MCH) - normal findings

  23-35 pg
• RBC indices ; mean corpuscular volume (MCV) - normal findings

  men: 80-98 um women: 78-102 um
• RBC indices ; mean corpuscular hemoglobin concentration (MCHC)

  proportion of each cell occupied by hemoglobin
• RBC indices ; mean corpuscular hemoglobin concentration (MCHC) - normal findings

  31-37%
• white blood cells


  count of the total number of wbc's in a cubic milimeter of blood
• white blood cells count ; normal findings

  4,500-11,000/mm
• platelet count

  fragments of cytoplasm that function in blood coagulation
• platelet count ; normal findings

  150,000-350,000/mm
• serum electrolytes

  routinely ordered as a screening test for electrolyte and acid base imbalances
• serum electrolytes

  routinely assessed for client at risk in the community
• serum electrolytes ; commonly ordered serum tests are

  sodium, potassium, chloride, and bicarbonate ions
• Normal electrolyte values for adults:

  • Sodium: 135-145 mEq/L
  • Potassium: 3.5-5.3 mEq/L
  • Chloride: 95-105 mEq/L
  • Calcium (total): 4.5-5.5 mEq/L or 8.5-10.5 mg/dL
  • Calcium (ionized): 56% of total calcium (2.5 or 4.0-5.0)
  • Magnesium: 1.5-2.5 mEq/L or 1.6-2.5
  • Phosphate: 1.8-2.6 (phosphorus)
  • Serum osmolality: 280-300 mOsm/kg water
• blood chemistry

  number of test may be performed on blood serum (the liquid portion of the blood)