Diagnostic Tests and Lab Procedures

Categories of Diagnostic Tests

• There are five general categories of diagnostic tests:
• Laboratory tests
• Radiology and imaging tests and procedures
• Ultrasonography
• Endoscoping examinations
• Graphic recording tests

Laboratory Tests

• Laboratory tests are a broad classification for numerous types of examinations performed on some type of body fluid
• Such as, whole blood or the serum portion of the blood, spinal fluid, sputum, urine, gastric contents, feces, and bone marrow.

Anatomy and Physiology Connection: Blood

• In adults, red blood cells (RBCs) are produced by the bone marrow within the sternum, vertebrae, ribs and pelvis
• The kidneys release a protein known as erythropoietin
• Erythropoietin acts on stem cells in the bone marrow to produce more RBCs
• The RBC life span is approximately 120 days
• White blood cells (WBCs) are mostly produced in the bone marrow, with limited production in the lymphoid tissues
• Platelets (PLTs) are produced from large bone cells known as megakaryocytes

Hematology

• Hematology is the study of blood cells and the blood-forming tissues (the bone marrow) including different types of blood counts

Complete Blood Count

• The most common test ordered is the complete blood cell count (CBC)
• The CBC measures the number of leukocytes (WBCs), erythrocytes (RBCs), and thrombocytes also called platelets (PLTs) in the blood
• It also measures the percentages of the five types of WBCs (Lymphocytes, neutrophils, eosinophils, basophils, and monocytes)
• Measures hemoglobin (Hgb) or iron pigment and the hematocrit (Hct), which is the percentage of packed RBCs compared with the whole blood volume
• Each of these tests may be ordered as a stand-alone

Word Building

• Radiology: radio + radiant energy + logy + study of
• Ultrasonography: ultra + extreme + sono + sound + graphy + writing Hematology: hemoto + blood + logy + study of

Nursing Responsibilities in Diagnostic Testing

• The nurse will have numerous reponsibilities relating to health-care provider-ordered diagnostic tests and procedures
• Responsibilities before the test include:
• Noting the health-care provider's order
• Occasionally scheduling the test or procedure
• Educating the patient regarding the process
• Ensuring the patient is not allergic to dyes, iodine, shellfish, or contrast medium that may be used for the test
• Administering laxatives or enemas material from the intestinal tract which allows for better visualization of the intestine for various imaging tests
• Obtaining consent if the procedure requires it
• Ensure the healthcare provider is answering all the patient's questions before consent is signed
• Knowing when to withhold food and fluids
• Preparing the patient
• Assisting the examiner with performance of the test or procedure

Nursing Responsibilities After Diagnostic Tests

• Obtaining specimens and/or delivering specimens to the laboratory
• Monitoring and assessing the patient's condition after the test
• Reassuring or supporting the patient as needed
• Notifying the health-care provider of significant abnormal results
• Monitoring for complications
• Providing necessary postprocedure nursing care
• Being able to relate the significance of the test findings to the patient's condition

Patient Teaching

• Prepare the patient for upcoming tests or procedures to alleviate the patient's anxiety and increase compliance
• Use terminology the patient can understand when explaining the purpose of the test or procedure and the test's benefits and dangers
• Describe what will occur, including any steps that must be performed before the test
• Explain how to properly obtain a specimen such as urine and sputum
• Provide the patent with written material to reinforce your teaching
• Ensure that all patient teaching is completed before written consent is signed

Settings Connection: Medical Office Diagnostic Testing and Results

• Many times licensed practical/vocational nurses working in medical offices or clinics will be the staff member who either sees the results of diagnostic texts first or the person who gets the telephone call about abnormal blood tests.
• It is important to recognize values that are severely abnormal and let the healthcare provider know about them right away
• You may also be responsible for scheduling diagnostic testing for patients and for giving them preparation instructions

When to Withhold Food and Fluids

• Withholding food and fluids known as keeping the patient NPO
• Tests that may require the patient be kept NPO for 6 to 8 hours include:
• Any type of endoscopy such as EGD and colonoscopy
• Cardiac catheterization
• Any CT with contrast medium or dye
• Any test reflecting glucose levels, such as the glucose tolerance test and fasting blood glucose
• Lung and brain scans if contrast medium is used
• Cholesterol and lipid tests