November is COPD Awareness Month—a time to shift conversations about chronic obstructive pulmonary disease from “something that happens to smokers” to a preventable and manageable condition with measurable warning signs and biomarkers that can inform earlier, smarter care.

The reality is both sobering and hopeful. COPD is the third leading cause of death globally, yet it remains vastly underdiagnosed. Many people experience years of symptoms—chronic cough, breathlessness, reduced exercise tolerance—before they’re formally evaluated. Others are diagnosed late, after significant lung damage has already occurred. But here’s the encouraging part: early detection, coupled with biomarker awareness and proactive monitoring, can change the trajectory of the disease.

This article is designed to help you understand not just COPD itself, but the measurable biological markers that add depth and context to your lung health story—and how those markers support better conversations with your healthcare team.

COPD Is Common—and Often Underdiagnosed

Chronic obstructive pulmonary disease affects over 16 million Americans (and hundreds of millions worldwide). Yet estimates suggest that roughly half of cases go undiagnosed, particularly in earlier stages when intervention is most effective.

Why the gap? Many people attribute persistent cough or breathlessness to ageing, deconditioning, or simply “smoker’s cough”—without realising it warrants medical evaluation. Others have mild symptoms and don’t push for spirometry testing. And some experience symptoms so gradually they adapt without seeking help.

The consequence is diagnosis often happens during an acute exacerbation—when someone ends up in the emergency department with severe breathlessness—rather than during routine screening. By then, significant airway damage may have already occurred.

The Importance of Early Lung Function Testing

Spirometry—a simple breathing test that measures how much air your lungs hold and how quickly you can exhale—is the gold standard for COPD diagnosis and monitoring. When combined with blood biomarkers that reflect genetic risk (alpha-1 antitrypsin deficiency) and systemic inflammation (CRP, fibrinogen), a fuller picture emerges.

This “dual approach” of spirometry plus biomarker awareness supports earlier detection, better risk stratification, and more informed long-term planning. It shifts COPD management from reactive crisis response to proactive, data-informed care.

What COPD Is (In Plain Language)

Before diving into biomarkers, it’s essential to understand what COPD actually is and why it matters.

Chronic obstructive pulmonary disease is a progressive lung condition characterised by persistent airflow limitation—your lungs gradually lose their ability to move air in and out efficiently. This limitation typically involves two overlapping processes: emphysema (destruction of lung tissue) and chronic bronchitis (inflammation and mucus in the airways).

Emphysema vs. Chronic Bronchitis

Emphysema is the destruction of alveoli—the tiny air sacs in the lungs where oxygen and carbon dioxide exchange happens. Think of alveoli as small balloons; in emphysema, the walls between these balloons break down, creating larger, less efficient air spaces. As a result, the lungs can hold air but can’t release it efficiently. People with emphysema often experience breathlessness, particularly with exertion.

Chronic bronchitis is inflammation of the airways (bronchi) that produce excessive mucus, leading to a persistent, productive cough. The inflammation and mucus obstruct airflow. Chronic bronchitis is often associated with smoking and biomass fuel exposure.

Most people with COPD have features of both conditions, though one may dominate the clinical picture. The key point is that both lead to airflow limitation—the hallmark of COPD.

Why Airflow Limitation Happens: Spirometry Basics

Spirometry measures two key numbers:

FEV1 (Forced Expiratory Volume in 1 second): How much air you can exhale in one second.

FVC (Forced Vital Capacity): The total amount of air you can exhale after a deep breath in.

The ratio FEV1/FVC is crucial. In healthy lungs, this ratio is 0.70 or higher (you can exhale at least 70% of your total lung capacity in the first second). If FEV1/FVC is below 0.70, airflow limitation is present—the defining feature of COPD.

From there, severity is staged using FEV1 alone: mild (FEV1 50–79% predicted), moderate (30–49%), severe (less than 30%), and very severe. These values guide conversations about treatment intensity, monitoring frequency, and risk stratification.

Why this matters: Spirometry provides objective evidence of lung function decline and helps distinguish COPD from other causes of breathlessness (asthma, heart disease, deconditioning). But spirometry doesn’t tell the whole story. That’s where blood biomarkers come in.

Key Biomarkers Linked to COPD Risk and Monitoring

Blood tests complement spirometry by revealing genetic risk factors and systemic inflammation patterns that influence disease progression and exacerbation likelihood. Three categories of biomarkers are particularly relevant to COPD awareness.

Alpha-1 Antitrypsin (AAT) and Genetic Risk

Alpha-1 antitrypsin is a protein produced by the liver that protects lung tissue from inflammation-related damage, particularly during infection or when exposed to irritants like smoke. In healthy people, AAT levels are sufficient to provide this protection.

However, roughly 1 in 2,500 to 1 in 3,000 people worldwide inherit a genetic mutation that dramatically reduces AAT production. This condition, called alpha-1 antitrypsin deficiency, means lung tissue is left vulnerable to damage—even in the absence of smoking or other major risk factors.

AAT deficiency is particularly important to screen for in:

  • People under 45 diagnosed with COPD (especially nonsmokers)
  • Individuals with early-onset emphysema
  • People with a family history of emphysema or early lung disease
  • Anyone with COPD who never smoked or had minimal smoking exposure
  • Relatives of diagnosed AAT-deficient individuals

An AAT level below 80 mg/dL is considered deficient. A level between 80 and 100 mg/dL is borderline and may warrant closer monitoring. Levels above 100 mg/dL are generally considered protective.

Why this matters: If you have AAT deficiency, several interventions become relevant—smoking avoidance is critical (the combination of deficiency and smoking accelerates emphysema dramatically), pulmonary function monitoring becomes more frequent, and in some cases, augmentation therapy (intravenous AAT replacement) may be considered in consultation with a specialist.

Importantly, AAT screening is not a one-time test. If you’re found to be borderline or deficient, genetic counselling and specialist pulmonology evaluation are important next steps. Some people with mild deficiency never develop COPD, whilst others with moderate deficiency progress more rapidly—individual factors matter enormously.

CRP and Systemic Inflammation

C-reactive protein (CRP) is a marker of systemic inflammation—elevated levels suggest your body is mounting an inflammatory response. In COPD, elevated CRP is associated with greater symptom burden, more frequent exacerbations, and poorer outcomes.

A CRP level below 3 mg/L is generally considered normal; levels above 10 mg/L indicate more substantial inflammation. In COPD patients, persistently elevated CRP—particularly levels above 5 mg/L—correlates with exacerbation risk and disease progression.

Why this matters for COPD: COPD is not just a lung disease; it’s a systemic inflammatory condition. Inflammation in the airways and lung tissue can spill over into the bloodstream, reflected in elevated CRP. When CRP is elevated, it signals that inflammation is active and exacerbation risk may be higher. This is particularly relevant heading into winter—a season of increased respiratory infections that can trigger exacerbations.

Tracking CRP over time helps identify patterns. If your CRP climbs during winter months or following illness, that pattern informs seasonal prevention strategies (vaccination, careful hand hygiene, consideration of prophylactic measures in consultation with your doctor).

Fibrinogen as an Acute-Phase Marker

Fibrinogen is a clotting factor that also acts as an acute-phase inflammatory protein. Elevated fibrinogen often accompanies acute infections and inflammation. In COPD, elevated fibrinogen is associated with increased exacerbation frequency and poorer outcomes.

Like CRP, fibrinogen reflects systemic inflammation and can be elevated during acute illness or during periods of chronic inflammatory activity.

Why this matters: Fibrinogen, alongside CRP, provides a fuller picture of your inflammatory status. Some people with COPD have elevated CRP but normal fibrinogen; others have both elevated. This distinction—whilst subtle—can help your clinician understand the nature of your inflammation and may guide monitoring or intervention decisions.

Eosinophil Count and Inhaled Steroid Response Context

Eosinophils are white blood cells involved in allergic and parasitic responses. In COPD, eosinophil count helps predict response to inhaled corticosteroids (ICS), a common COPD medication.

An eosinophil count above 300 cells/µL in people with COPD is associated with better response to ICS therapy. Conversely, low eosinophil counts (<100 cells/µL) suggest ICS may offer minimal benefit, and other medication approaches might be prioritised.

Why this matters: COPD treatment is increasingly personalised. If you’re prescribed an inhaled corticosteroid, knowing your eosinophil count helps predict whether that medication is likely to benefit you. This isn’t a hard rule—many factors influence ICS response—but eosinophil counts are one useful data point that supports more tailored therapy decisions.

Spirometry and Blood Tests – How They Work Together

Spirometry tells you about lung function. Blood biomarkers tell you about disease mechanisms, genetic risk, and inflammatory status. Together, they paint a more complete picture than either alone.

What FEV1 and FEV1/FVC Indicate

Your FEV1 and FEV1/FVC ratio define whether airflow limitation is present and how severe it is. But FEV1 alone doesn’t explain why airflow is limited or how fast the disease is progressing.

For example, two people might have the same FEV1 percentage but very different disease trajectories:

  • Person A has borderline AAT deficiency, high CRP, frequent exacerbations, and rapid FEV1 decline.
  • Person B has normal AAT, normal CRP, rare exacerbations, and stable FEV1.

Without biomarker context, both look similar on spirometry. With it, you understand that Person A requires more aggressive monitoring and intervention, whilst Person B may benefit from a more conservative approach.

When Blood Biomarkers Add Extra Context

Blood biomarkers become particularly valuable in several scenarios:

Suspected AAT deficiency: If you’re young, nonsmoking, or have early-onset COPD, AAT testing clarifies whether genetic risk is a factor and guides specialist care and family screening.

Frequent exacerbations: If you’re having multiple exacerbations per year despite optimal inhaler therapy, elevated CRP and fibrinogen may signal that systemic inflammation is a key driver. This might prompt additional therapies targeting inflammation or closer monitoring for triggers.

Unclear disease progression: If your FEV1 is declining faster than expected, biomarkers help identify whether aggressive inflammation, genetic factors, or other contributors are at play.

Therapy optimisation: Eosinophil counts inform ICS prescribing decisions, helping ensure you’re on medications that are actually beneficial for your particular biology.

Who May Benefit Most From AAT and Inflammation Testing

Not everyone with COPD needs the full battery of biomarker testing. Risk stratification helps identify who benefits most.

Current and Former Smokers

Smoking causes roughly 85% of COPD cases in developed countries. Current and former smokers with respiratory symptoms or a confirmed COPD diagnosis benefit significantly from:

  • Spirometry to assess lung function and stage disease
  • CRP and fibrinogen to understand inflammatory burden and exacerbation risk
  • AAT testing especially if COPD onset was early (before age 45) or if there’s family history of emphysema

For smokers, AAT is particularly important because AAT deficiency dramatically accelerates emphysema in the presence of smoking. Even if you’ve quit, knowing your AAT status informs risk management and surveillance intensity going forward.

Younger Adults With Unexplained Dyspnea

Breathlessness in someone under 40, particularly without significant smoking history, raises the question of AAT deficiency. Other causes include asthma, pulmonary hypertension, or heart disease, but AAT deficiency should be systematically ruled out.

Testing is straightforward: a blood sample yields AAT level and, if low, genetic testing (Pi typing) to confirm the specific deficiency pattern (PiZZ is the most severe form).

Individuals With Frequent Exacerbations

An exacerbation is an acute worsening of symptoms—typically triggered by respiratory infection—that may require antibiotics, oral corticosteroids, or hospitalisation. If you’re experiencing three or more exacerbations annually despite optimised inhaler therapy, biomarker evaluation helps identify drivers:

  • Elevated CRP/fibrinogen may warrant anti-inflammatory strategies
  • Low eosinophils may mean you’re on unnecessary ICS
  • Undiagnosed AAT deficiency may explain disease severity

Understanding the underlying biology helps your pulmonologist tailor your regimen more effectively.

What These Biomarkers Can (and Cannot) Tell You

Screening vs. Diagnosis

This distinction is critical: biomarkers support screening and risk assessment, but they don’t diagnose COPD or predict your individual future with certainty.

AAT testing can reveal whether you carry a genetic deficiency, but not everyone with AAT deficiency develops COPD. Similarly, someone with normal AAT and heavy smoking exposure absolutely can develop COPD. AAT status is one piece of the risk puzzle, not a destiny.

CRP and fibrinogen indicate current inflammatory status but don’t predict future exacerbations with certainty. They provide context and may inform monitoring intensity or prevention strategies, but many other factors influence exacerbation risk (immune function, infection exposure, medication adherence, etc.).

Eosinophil counts help predict ICS response but don’t determine it with absolute certainty. Individual variation is substantial.

The key is understanding these biomarkers as supporting information that enhances clinical decision-making, not as standalone diagnostic or predictive tools.

Monitoring Trends Over Time

The real power of biomarkers emerges when you track them over time.

A single CRP value tells you current inflammation status. But CRP measured quarterly over a year reveals patterns:

  • Does CRP spike during winter? (Suggests seasonal exacerbation risk; informs prevention strategy)
  • Does CRP rise after illness? (Expected; monitoring for resolution helps track recovery)
  • Is CRP chronically elevated despite optimised therapy? (May warrant additional anti-inflammatory measures)

Similarly, FEV1 measured once every 1–2 years shows whether lung function is stable, declining slowly, or declining rapidly. That trajectory, combined with biomarker trends, informs how aggressively disease is progressing and whether therapy adjustments are needed.

Taking Ownership of Your Lung Health Data

COPD is a chronic condition you’ll manage over years or decades. Empowerment comes from understanding your own biology and actively participating in monitoring and care decisions.

Building a Baseline

A baseline is your starting point—spirometry, AAT (if indicated), CRP, fibrinogen, and eosinophil count—measured when you’re in stable condition (not during an acute exacerbation).

Baseline values matter because they become your reference point. Future tests are compared to this baseline:

  • Is FEV1 stable, slightly declining, or rapidly declining?
  • Is CRP climbing or remaining stable?
  • How does current status compare to where you started?

If you haven’t had baseline testing and have COPD or COPD risk factors, asking your doctor for spirometry and relevant blood work during your next appointment is a valuable step. If you’ve already been tested, obtaining copies of your results and understanding what they mean is part of building ownership.

Preparing for Pulmonology Conversations

When you meet with a pulmonologist (or primary care doctor managing COPD), bring:

  • Your symptom timeline: When did symptoms start? What’s worsened? What’s improved?
  • Spirometry results (yours and, if possible, from previous years to show trajectory)
  • Blood biomarker results (AAT, CRP, fibrinogen, eosinophils)
  • Exacerbation log: How many exacerbations in the past year? When did they occur? What triggered them?
  • Current medications and how you’re using them: Are you actually using your inhalers? Are they helping?
  • Specific questions or concerns

Walking in with this information shifts the conversation. Rather than providing vague descriptions of breathlessness, you’re presenting objective data and asking informed questions about what it means and what to do next. This collaborative approach often leads to better outcomes.

Tracking Symptoms and Environmental Factors

Beyond lab tests, symptom tracking provides invaluable context. A simple log can record:

  • Daily or weekly breathlessness: On a scale of 0–10, how short of breath are you?
  • Exertion tolerance: How far can you walk before becoming breathless?
  • Cough and sputum: Is your cough productive? What colour is sputum?
  • Sleep quality: Are you waking at night due to breathing difficulty?
  • Infection exposure: Are family members or coworkers ill?
  • Environmental triggers: Pollution, allergens, smoke, temperature changes
  • Medication adherence: Are you taking inhalers as prescribed?

Over weeks and months, patterns emerge. Maybe you notice that poor air quality days correlate with increased symptoms, or that missing inhaler doses predicts worse breathlessness. These patterns inform both prevention strategies and conversations with your healthcare team.

Reducing Anxiety, Building Confidence

COPD is a serious condition, but it’s not a death sentence—particularly when caught early and managed proactively. Understanding your lung function, genetic risk, and inflammatory status transforms COPD from a mysterious, frightening condition into a measurable, manageable health challenge.

Knowledge reduces anxiety. When you understand what spirometry means, what your AAT level tells you, and what CRP reflects, symptoms become less scary and testing becomes less mystifying. You move from feeling helpless to feeling informed and engaged.

That shift—from reactive crisis management to proactive data-informed care—is where real confidence emerges.

A Note on Testing and Pulmonary Care

The information in this article is educational and meant to support informed conversations with your healthcare provider, not replace medical evaluation or advice. Spirometry and blood biomarkers are tools that support screening, diagnosis, and monitoring, but they must be interpreted within the full clinical context of your symptoms, medical history, and examination findings.

If you’re experiencing persistent cough, shortness of breath, or other respiratory symptoms, or if you have known COPD and questions about your management, speak with your primary care doctor or a pulmonologist. They can assess your individual situation, order appropriate testing, and recommend next steps tailored to your specific health needs.

Organisations like the COPD Foundation, the CDC, and the Global Initiative for Chronic Obstructive Lung Disease (GOLD) provide evidence-based resources on COPD prevention, diagnosis, and management. Consulting these resources alongside professional medical guidance ensures you’re getting accurate, current information.

Additionally, pulmonary rehabilitation—structured exercise, education, and support programmes for people with COPD—can significantly improve function and quality of life. Ask your doctor whether pulmonary rehabilitation is appropriate for you.

Key Takeaways

  • COPD is common and often underdiagnosed. Early detection through spirometry screening can support better long-term outcomes.
  • Alpha-1 antitrypsin deficiency is a genetic risk factor for early emphysema that should be screened for in younger people, nonsmokers, or those with early-onset disease.
  • Systemic inflammation markers (CRP, fibrinogen) provide context for exacerbation risk and disease progression and can inform monitoring intensity and prevention strategies.
  • Eosinophil counts help predict inhaled corticosteroid response, supporting more personalised medication decisions.
  • Biomarkers complement spirometry; neither tells the whole story alone. Together, they support earlier detection, better risk stratification, and more informed care planning.
  • Building a baseline of lung function and biomarkers, tracking trends over time, and actively participating in your care leads to better outcomes and greater confidence in managing your health.

This COPD Awareness Month, whether you’re at risk, recently diagnosed, or managing known COPD, take a moment to think about your lung health. If you have symptoms, don’t wait—seek evaluation. If you’ve been diagnosed, ask about baseline biomarker testing and how you can actively participate in monitoring. If you’re a family member or friend of someone with COPD, ask how you can support them.

Understanding COPD at the biological level—through spirometry and biomarkers—transforms it from a mysterious, frightening condition into something measurable and manageable. That understanding is your first step toward better, more confident health.