Laboratory Data

• What is the primary purpose of clinical laboratory tests?

  To evaluate patients' health status and identify organ-system dysfunction
• How many major disciplines is laboratory medicine divided into?

  Five major disciplines
• What are the five major disciplines of laboratory medicine?

  • Clinical Biochemistry
  • Hematology
  • Microbiology
  • Immunology
  • Anatomic Pathology
• What does the reference range represent in laboratory tests?

  The expected range of values considered to be "normal"
• What are biological reference intervals also known as?

  Expected values
• What factors can cause variations in reference ranges?

  Age, gender, race, and ethnicity
• What is a critical test value?

  A result significantly outside of the reference range
• Why must critical values be communicated with caregivers?

  Because they may represent a potentially life-threatening condition
• What does a Complete Blood Count (CBC) examine?

  • Counts leukocytes (white blood cells)
  • Evaluates erythrocytes (red blood cells) for size and hemoglobin content
  • Counts thrombocytes (platelets)
• What is leukocytosis?

  A WBC count above normal
• What conditions can cause leukocytosis?

  Infection, stress, and trauma
• What does leukopenia represent?

  A WBC count below normal
• What can cause leukopenia?

  Overwhelming infections and certain cancer therapies
• What are the five varieties of white blood cells?

  • Neutrophils (40-75%)
  • Eosinophils (0-6%)
  • Basophils (0-1%)
  • Monocytes (2-10%)
  • Lymphocytes (20-45%)
• What is neutrophilia?

  Elevation of absolute value of neutrophils
• What does the presence of bands and segmented neutrophils indicate?

  More severe bacterial infection
• What is neutropenia?

  Reduced number of circulating neutrophils
• What can cause neutropenia?

  Bone marrow disease such as lymphoma or leukemia
• What is the rule of thumb regarding WBC count elevation?

  • Usually caused by an increase in neutrophils or lymphocytes
  • Severity of bacterial pneumonia assessed by neutrophil increase
• What is anemia?

  Reduced RBC count
• What causes anemia?

  Blood loss or reduced RBC production by bone marrow
• What is polycythemia?

  Abnormal elevation of RBC count
• What can cause secondary polycythemia?

  Bone marrow stimulation due to chronically low blood oxygen levels
• What is hemoglobin's role?

  To bond with oxygen
• What is the normal hemoglobin concentration range?

  12-17 g/dL
• What happens to RBCs with reduced hemoglobin?

  They are smaller than normal and lack normal color
• What does hematocrit measure?

  The ratio of RBC volume to that of whole blood
• What can low hematocrit levels indicate?

  Anemia or over-hydration
• What can high hematocrit levels indicate?

  Polycythemia and dehydration
• Why is homeostasis important for normal cellular function?

  It maintains a dynamic balance or equilibrium
• What are electrolytes?

  Charged ions influencing the functioning of enzymes
• What does a basic chemistry panel include?

  • Sodium (Na+)
  • Potassium (K+)
  • Chloride (Cl-)
  • Total CO2/bicarbonate
  • Glucose (GL)
  • Creatinine (Cr) & blood urea nitrogen (BUN)
• What is hyperglycemia?

  Elevation of blood glucose
• What can cause hypoglycemia?

  Inadequate diet or drug-induced effects
• How is diabetes diagnosed?

  By fasting blood glucose levels >140 mg/dL on two occasions
• What does an anion gap indicate?

  Disruption of normal anion balance or presence of abnormal acid anion
• What is the normal anion gap range?

  1. 14 mmol/L
• What is lactate?

  The end product of anaerobic glucose metabolism
• What can high lactate levels indicate?

  Overproduction or insufficient metabolism resulting in lactate acidosis
• What is the significance of elevated hepatic enzymes?

  They indicate liver damage