Hemoptysis laboratory findings

There are laboratory tests that are helpful for diagnosis the underlying cause of hemoptysis. Sputum must be evaluated for the cytology, gram stain, culture, and acid-fast stain. Arterial blood gases might show hypoxia. Complete blood count (CBC) might show elevated WBC, low platelet, and anemia. Signs of dehydration might be detected in laboratory tests such as BUN, Cr, urinalysis, or electrolytes. Coagulation studies might be abnormal.

• There are laboratory tests that are helpful for diagnosis the underlying cause of hemoptysis.^[1][2][3]
  • Sputum analysis provides valuable information about the cause of hemoptysis. Sputum must be evaluated for the followings:
    • Cytology
    • Gram stain
    • Culture
    • Acid-fast stain
  • Laboratory tests that might be abnormal in a patient with hemoptysis:
    • Arterial blood gases might show:
      • Hypoxia (normal PaO2 75-100 mm Hg)
    • Blood urea nitrogen might be elevated (normal BUN 8 to 20 mg/dL)
    • Creatinine might be elevated (normal Cr 0.5 to 1.0 mg/dL for women and 0.7 to 1.2 mg/dL for men)
    • Complete blood count (CBC) might show:
      • Elevated WBC (normal WBC 4-10 x 10^9/L )
      • Low platelet (normal platelet 150-400 x 10^9/L)
      • Anemia (normal Hb 12-15 g/dL for women, 13-17 g/dL for men)
    • Coagulation studies might show:
      • Elevated prothrombin time (normal PT 11-14 sec)
      • Elevated partial thromboplastin time (normal aPTT 20-40 sec)
    • Urinalysis might show:
      • Hematuria (normal RBC in urine <5)
    • Electrolytes
      • Elevated potassium (normal K 3.5-5 mmol/L)