Diagnostic Values and Specimen Collection Notes
Diagnostic Values and Specimen Collection
General Learning Objectives
- Explain the purpose for testing, the significance of abnormal results, how results guide treatment, and the implications for care regarding the following tests:
- Culture and sensitivity
- Complete blood count
- Coagulation studies
- Serum protein
- Liver enzymes
- Describe sensitivity testing and its meaning.
- Recognize the significance of imbalances to the following electrolyte levels in the care of a patient:
- Sodium
- Potassium
- Magnesium
- Calcium
- Recognize the significance of abnormal lab results and the need to report these to the charge nurse and/or physician.
- Expand on the important sequence of communication and collaboration within the healthcare team (e.g., SBAR) as it pertains to diagnostic testing.
- Describe the meaning of critical lab results and the communication requirements when critical results are received.
- Explain the appropriate collection method, rationale, and significance of results related to sputum testing for:
- Acid-fast bacillus (M. tuberculosis)
- Culture and sensitivity
- Cytology
General Diagnostic Tests – Discussion
- Purpose of diagnostic testing:
- Establish __.
- Guide __.
- Monitor __.
- Provide __.
- Role of the practical nurse regarding diagnostic testing and lab values:
- Have the knowledge and ability to diagnostic tests and lab values commonly used in health care
Culture and Sensitivity Testing
- Culture: Unknown definition.
- Sensitivity test: Unknown definition.
- Culture collection sites: Unknown where a culture can be collected from.
Complete Blood Count (CBC)
- Provides information about the kinds and numbers of cells in the blood including:
- Red blood cells (RBC’s) aka erythrocytes
- Hemoglobin (Hgb)
- Hematocrit or packed cell volume (PCV)
- Platelets aka thrombocytes
- White blood cell types (WBC)
- Neutrophils
- Lymphocytes
- Monocytes
- Eosinophils
- Basophils
Complete Blood Count (CBC) – Continued Discussion:
- What is the purpose of red blood cells (RBC’s) aka erythrocytes?
- What is hemoglobin? (Hb/ Hgb)?
- What is the purpose of white blood cells (WBC’s)?
- What is hematocrit (Hct)?
- What is the role of platelets aka thrombocytes?
Coagulation Studies
- Blood-clotting studies used to diagnose bleeding and clotting disorders that include:
- Prothrombin Time (PT)
- Monitor patients on warfarin therapy
- Partial Thromboplastin time (PTT)
- Monitor patients on heparin therapy
- International Normalized Ratio (INR)
- Monitor patients on warfarin therapy
- D-dimer (DDIMER)
Serum Protein
- What is the purpose of protein in the blood?
- Albumin
- A protein made in the that maintains colloidal __.
- Carries medicine and hormones through the body
- Helps with tissue growth and healing
- Globulin
- A group of proteins that help fight __ and transport nutrients
Liver Enzymes
- Measure specific enzymes and proteins in the blood. Increased levels can indicate liver damage. These tests include:
- Alanine transaminase (ALT)
- Aspartate aminotransferase (AST)
- Alkaline phosphatase (ALP)
- Bilirubin (not a LO)
- Found in bile and processed by the liver – it is a yellow pigmented waste product from RBC breakdown
- In patients with impaired liver function, bilirubin builds up resulting in jaundice
Sodium (Na+)
- Major extracellular cation
- Main function of sodium:
- To help maintain blood pressure, blood volume, and pH balance
- Wherever sodium goes, water goes
- Normal serum sodium range:
- 135-145 {mmol/L} (or mEq/L)
- What is the difference between hypernatremia and hyponatremia?
Potassium (K+)
- Major intracellular cation
- Main function of potassium:
- Heart and muscle contraction
- Normal serum potassium range:
- 3.5 to 5.0 {mmol/L} (or mEq/L)
- What is the difference between hyperkalemia and hypokalemia?
Magnesium (Mg)
- What is the function of magnesium in the body?
- Needed for proper muscle, nerve, and enzyme function
- Helps body use energy
- Moves potassium and sodium in and out of cells
- Required for calcium and vitamin D absorption
- What is normal serum magnesium range?
Calcium
- What are the main functions of calcium?
- 3 “B’s” – Bones, blood, and beats
- What is the normal serum calcium range?
Sputum Collection
- Acid-fast bacillus (AFB): Detects pulmonary tuberculosis
- Culture and sensitivity: Identifies specific microorganisms and their antibiotic sensitivity
- Cytology: Helps to identify abnormal cells
- Discussion:
- When is the ideal time for sputum to be collected?
- What part of the respiratory tract should the sputum come from?
- A patient expectorates a large amount of thick sputum into a tissue. Can this be sent to the lab?
Communicating Lab Results
- All laboratories have policies to clearly identify critical high and low values and to alert patients, unit staff, and physicians regarding results
- A critical value/result is a variance from normal (expected values) classified to be life-threatening unless something is done promptly and for which some corrective action could be taken
- Discussion: How should the health care provider communicate lab results?
Communicating Test Results Using SBAR
- Situation: what results you are concerned about. Potassium is 3.2
- Background: relevant history that pertains to phone call and why patient is in the hospital. Patient admitted Jan 29 with a bowel obstruction, had a resection on February 2, and is not tolerating clear fluids well, persistent nausea and vomiting.
- Assessment: data collection prior to phone call. Vitals signs within normal limits (list), decreased skin turgor, hypoactive bowel sounds etc.
- Recommendation: what are you suspecting. Request additional antiemetics, K+ replacement, possible imagining to ascertain if resection resolved bowel obstruction.
- What to talk about:
- Normal vs abnormal results
- Trend of lab values
- Lab values and patient symptoms
- Pre-op and post-op lab results
