Overview of Pulmonary Function Tests (PFTs) / 878

• Pulmonary Physiology / 878

• Purpose of Tests / 878

• Indications for PFTs / 878

• Classification of Tests / 878

• Symbols and Abbreviations / 879

Tests for Airway Flow Rates, Lung Volume, and Lung Capacity / 880

• Spirometry, Helium Dilution Test, Nitrogen Washout, Body Plethysmography / 881

• Forced Vital Capacity (FVC) / 883

• Peak Inspiratory Flow Rate (PIFR) / 885

• Peak Expiratory Flow Rate (PEFR) / 886

• Functional Residual Capacity (FRC) / 887

• Residual Volume (RV) / 888

• Expiratory Reserve Volume (ERV) / 889

• Inspiratory Capacity (IC) / 890

• Vital Capacity (VC) / 890

• Tidal Volume (V_T) / 891

• Inspiratory Reserve Volume (IRV) / 892

• Total Lung Capacity (TLC) / 892

Other Pulmonary Function Tests / 893

• Diffusing Capacity of the Lungs for Carbon Monoxide (Dlco) Test / 893

• Maximal Voluntary Ventilation (MVV) / 895

• Maximal Respiratory Pressure (MRP), Maximal Expiratory Pressure (MEP), Maximal Inspiratory Pressure (MIP) / 896

• Closing Volume (CV) / 897

• Volume of Isoflow / 898

• Thoracic Gas Volume (Vtg), Lung Compliance (Cl), Airway Resistance (R_aw), Airway Conductance (G_aw) / 898

• Bronchial Provocation Tests: Methacholine Challenge, Histamine Challenge / 900

• Cardiopulmonary Exercise Test (CPET) / 901

Gas Exchange Tests / 903

• Arterial Blood Gas (ABG) Analysis / 903

• Alveolar-Arterial Gradient (A-a Gradient); Arterial/Alveolar Oxygen Ratio (a/A Ratio) / 906

• Partial Pressure of Carbon Dioxide (Pco₂) / 907

• Oxygen Saturation (So₂) / 909

• Arterial Oxygen Content (Cao₂); Mixed Venous Oxygen Content (Cvo₂) / 911

• Partial Pressure of Oxygen (Po₂) / 912

• Total Carbon Dioxide Content (Tco₂) / 913

• Blood pH / 917

• Base Excess or Deficit / 919

• Lactic Acid (Lactate) / 920

Electrolyte Tests / 921

• Calcium (Ca²⁺) Level / 922

• Chloride (Cl⁻) Level / 925

• Phosphate (PO₄) Level / 927

• Magnesium (Mg²⁺) Level / 928

• Potassium (K⁺) Level / 931

• Sodium (Na⁺) Level / 934

• Bicarbonate (HCO₃⁻) Level / 936

• Anion Gap (AG) / 937

• Osmolality and Water-Load Test (Water-Loading Antidiuretic Hormone [ADH] Suppression Test) / 940

• Sweat Test / 943