A 23-year-old woman presents with shortness of breath, wheezing, chest wall pain and dry cough. Which initial tests should be ordered to evaluate suspected asthma?

A 23-year-old woman presents with shortness of breath, wheezing, chest wall pain and dry cough. Which initial tests should be ordered to evaluate suspected asthma?

• A. Chest X-ray and Spirometry
• B. Methacholine Challenge Test
• C. CBC Showing Eosinophils
• D. Peak Expiratory Flow Rate Alone

Answer: (A)

The main idea is to use objective lung function testing to confirm reversible airway obstruction, which is characteristic of asthma, while also ruling out other conditions that can mimic asthma. Spirometry with bronchodilator administration is the essential initial test because it shows whether there is obstructive airflow that improves after a bronchodilator. An improvement in FEV1 (and often FEV1/FVC) after inhaled bronchodilator supports asthma as the diagnosis. A chest X-ray is added at the outset to exclude alternative explanations for the symptoms, such as pneumonia, pneumothorax, or other lung pathology, especially when chest pain or atypical features are present. Together, chest X-ray plus spirometry provides both the rule-out and the confirmatory pieces needed in the initial evaluation. The other options aren’t as suitable as first-line tests. A methacholine challenge helps only when baseline spirometry is nondiagnostic and carries more risk, so it’s not an initial test. A CBC showing eosinophils can be seen with many conditions and isn’t diagnostic for asthma. Relying on peak expiratory flow rate alone doesn’t confirm asthma, as it is more useful for monitoring disease control and variability rather than establishing the diagnosis.

The main idea is to use objective lung function testing to confirm reversible airway obstruction, which is characteristic of asthma, while also ruling out other conditions that can mimic asthma. Spirometry with bronchodilator administration is the essential initial test because it shows whether there is obstructive airflow that improves after a bronchodilator. An improvement in FEV1 (and often FEV1/FVC) after inhaled bronchodilator supports asthma as the diagnosis.

A chest X-ray is added at the outset to exclude alternative explanations for the symptoms, such as pneumonia, pneumothorax, or other lung pathology, especially when chest pain or atypical features are present. Together, chest X-ray plus spirometry provides both the rule-out and the confirmatory pieces needed in the initial evaluation.

The other options aren’t as suitable as first-line tests. A methacholine challenge helps only when baseline spirometry is nondiagnostic and carries more risk, so it’s not an initial test. A CBC showing eosinophils can be seen with many conditions and isn’t diagnostic for asthma. Relying on peak expiratory flow rate alone doesn’t confirm asthma, as it is more useful for monitoring disease control and variability rather than establishing the diagnosis.