A 48-year-old person is suspected of having COPD. Which of the following tests is required to confirm the diagnosis?

Appeared in: MP CHO - 2022

Explanation

Spirometry is the gold standard and essential test for diagnosing COPD.
It provides an objective measurement of airflow limitation, which is the key feature of the disease.
A post-bronchodilator Forced Expiratory Volume in 1 second (FEV1) to Forced Vital Capacity (FVC) ratio of less than 0.70 confirms the diagnosis.
The results are also used to classify the severity of COPD (e.g., GOLD stages), which helps guide management and prognosis.

Option A: A Complete Blood Count (CBC) does not measure lung function. It is used to assess for complications of chronic COPD, such as polycythemia (secondary to chronic hypoxemia), or to detect anemia or infection.
Option C: 'HV level' is not a standard medical abbreviation or a recognized diagnostic test for any respiratory condition, including COPD. It is likely a typographical error.
Option D: C-Reactive Protein (CRP) is a non-specific marker of inflammation. While levels may be elevated in COPD, particularly during exacerbations, it is not diagnostic as many other conditions can also cause a high CRP.

Clinical Relevance

Nursing practice connection: Use the key finding related to Diagnostic confirmation of Chronic Obstructive Pulmonary Disease (COPD) to guide bedside assessment, documentation, and the next nursing action.
Accurate diagnosis of COPD via spirometry is the critical first step for initiating appropriate management, which includes smoking cessation, pharmacotherapy (bronchodilators), and pulmonary rehabilitation.
Staging the severity of COPD using FEV1 results allows the nurse and healthcare team to predict prognosis, tailor treatment intensity, and educate the patient about their condition.
Nurses play a key role in preparing and coaching patients for spirometry to ensure accurate and reliable results.

How to Approach the Question

First, identify the core of the question: it asks for the confirmatory diagnostic test for COPD.
Recall the fundamental pathophysiology of COPD, which is a disease of persistent airflow limitation.
Think about which test directly measures airflow and lung capacity. This points towards pulmonary function tests.
Evaluate the options provided. Spirometry is a direct measure of airflow. A Complete Blood Count and CRP are blood tests that measure systemic responses (like red cell count or inflammation), not the primary lung defect. 'HV level' is not a standard test.
Conclude that spirometry is the only option that can objectively demonstrate the airflow limitation required to confirm a COPD diagnosis.

Concept Tested & Keywords

Concept Tested: Diagnostic confirmation of Chronic Obstructive Pulmonary Disease (COPD)
Stem keywords: COPD, confirm diagnosis, test
Lead-in keywords: required to confirm
Clinical cues: suspected of having COPD
Negative lead-in flag: false

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E6 Medicine Davidson Principles Practice 24e p. 595-597

E6 Medicine Harrison 22e Part 2 p. 159-161

Practise the full MP CHO - 2022

Attempt every question from this paper in a timed mock, then review the full solution for each one.