Lab and Diagnostic Testing

• Diagnostic tests, commonly called laboratory tests are tools that provide information about the client
• Blood tests are commonly used diagnostic tests that

  can provide valuable information about the

  hematologic system and many other body systems.
• A venipuncture is a puncture of a vein for collection of a blood specimen
• A phlebotomist is a person from a laboratory who

  performs venipuncture and usually collects the blood specimen for the tests ordered by the primary care provider .
• complete blood count is a basic screening test and one of the most frequently ordered blood tests.

  It includes hemoglobin and hematocrit measurements, erythrocyte (red blood cells) count, leukocyte (white blood cell) count, red blood cell indices, and a differential white cell count.
• Serum electrolytes are often routinely ordered for

  any client admitted to a hospital as a screening test

  for electrolyte and acid–base imbalances.
• The most commonly ordered serum tests are for

  sodium, potassium, chloride, and bicarbonate ions.
• A blood chemistry includes a number of other tests may be performed on blood serum (the liquid portion of the blood).
• Specimen collection and testing is when a nurse collects specimens of body fluids for the assessment of client's health status
• clean voided urine specimens for routine

  urinalysis
• clean-catch or midstream urine specimens for

  urine culture
• timed urine specimens for a variety of tests that

  depend on the client’s specific health problem.
• Specific gravity is an indicator of urine

  concentration, or the amount of solutes (metabolic

  wastes and electrolytes) present in the urine.
• The specific gravity of distilled water is 1.00
• the specific gravity of urine normally ranges from 1.010 to 1.025
• Urinary pH is measured to determine the relative

  acidity or alkalinity of urine and assess the client’s

  acid–base status.
• Urine normally is slightly acidic, with an average pH of 6
• Urine is tested for glucose to screen clients

  for diabetes mellitus and to assess clients during

  pregnancy for abnormal glucose tolerance.
• Protein molecules normally are too large to escape

  from glomerular capillaries into the filtrat
• Urine testing for the presence of protein generally is done with a reagent strip or dipstick
• Visualization procedures include indirect visualization (non-invasive) and direct visualization (invasive) techniques for visualizing body organ and system functions.
• Electrocardiography provides a graphic recording of the heart’s electrical activity.
• electrocardiogram can be examined to detect dysrhythmias and alterations in conduction indicative of myocardial damage, enlargement of the heart, or drug effects
• Stress electrocardiography uses ECGs to assess the client’s response to an increased cardiac workload during exercise
• Angiography is an invasive procedure requiring informed consent of the client. It uses fluoroscopy and x-rays to assess the flow through vessels and areas of narrowing or blockage.
• In angiography, radiopaque dye is injected into the vessels to be examined
• Computed tomography is also called CT scanning, computerized tomography or computerized axial tomography (CAT)
• Computerized tomography is a painless,

  noninvasive x-ray procedure that has the

  unique capability of distinguishing minor

  differences in the density of tissues
• Magnetic resonance imaging is a noninvasive diagnostic scanning technique in which the client is placed in a magnetic field.
• The MRI is commonly used for visualization of

  the brain, spine, limbs and joints, heart, blood

  vessels, abdomen, and pelvis.
• MRI procedure lasts between 60 and 90 minutes
• Diagnostic testing involves three phases:

  pretest, intratest, and post-test.