Investigations

1st investigations to order

Test
Result
Test

Acute bronchitis is generally diagnosed clinically, though tests may be needed to exclude other diagnoses such as asthma or pneumonia.

Result

features of acute bronchitis

Investigations to consider

Test
Result
Test

Not recommended in patients with acute bronchitis but can be helpful in evaluating for asthma; pulmonary function will improve over time with acute bronchitis.

Result

mild/moderate bronchial obstruction

Test
Result
Test

May be helpful to rule out pneumonia as cause of cough and fever.

Result

normal

Test
Result
Test

Should be ordered if after clinical assessment a diagnosis of pneumonia has not been made, and antibiotic therapy is being considered to help guide therapy. Point of care testing may be considered in primary care.[13]

Result

<20 mg/L (no antibiotics); 20-100 mg/L (delayed antibiotics); >100 mg/L (immediate antibiotics)

Emerging tests

Test
Result
Test

Emerging as a promising biomarker for the diagnosis of bacterial infections as it tends to be higher in severe bacterial infections and low in viral infections.

The Food and Drug Administration has approved procalcitonin as a test for guiding antibiotic therapy in patients with acute respiratory tract infections.

A Cochrane review of studies employing procalcitonin to differentiate between bacterial versus viral respiratory infections may indicate some value in reducing the use of antibiotics for this condition. Although most patients in the study had pneumonia, sepsis, or other potentially serious infections, the study did include a subset of patients who presented with acute bronchitis and had reductions in antibiotic use when this test was used. Further research is required.[15]

Result

elevated

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