What lab work is ordered for a patient with tachypnea?

For a patient with tachypnea (abnormally rapid breathing), several laboratory tests should be ordered to determine the underlying cause. Initial lab work typically includes arterial blood gas (ABG) analysis to assess oxygenation, ventilation, and acid-base status; complete blood count (CBC) to check for anemia or infection; basic metabolic panel to evaluate electrolyte imbalances, kidney function, and acid-base disturbances; and cardiac biomarkers like troponin and BNP to rule out cardiac causes. Additional tests often include chest X-ray to visualize the lungs and heart; pulse oximetry for continuous oxygen saturation monitoring; and D-dimer if pulmonary embolism is suspected. Depending on clinical presentation, further testing may include lactate levels to assess tissue perfusion, thyroid function tests if hyperthyroidism is suspected, toxicology screening for drug-induced causes, and pulmonary function tests to evaluate for underlying lung disease. These tests help identify whether tachypnea is due to respiratory, cardiac, metabolic, or other systemic conditions, allowing for appropriate treatment of the underlying cause.