Asthma is one of the most common long-term conditions in the UK, affecting both adults and children. While the symptoms—such as wheezing, coughing, and shortness of breath—can be obvious, confirming a diagnosis often requires proper medical testing. If you’re wondering how doctors test for asthma or whether a blood test for asthma is available, this guide breaks down everything you need to know.
Asthma can sometimes be mistaken for other breathing problems such as allergies, infections, or even heart conditions. Getting the right tests helps doctors:
At Private Medical Clinic, we provide comprehensive health checks and specialist referrals to ensure you get accurate answers and timely support.
Doctors use a mix of history-taking, physical examination, and diagnostic tests. Here are the most common methods:
Your GP or private doctor will start by asking about:
These are the gold standard in diagnosing asthma.
This involves blowing into a machine to measure how much air you can breathe in and out, and how quickly. If results improve after using an inhaler, it’s a strong sign of asthma.
A small handheld device checks how fast you can blow air out. Recording daily results over time helps spot patterns.
Sometimes asthma symptoms don’t show up in routine testing. In these cases, doctors may:
While there isn’t a single blood test for asthma that gives a yes or no answer, blood tests can be useful. They may check for raised eosinophils (a type of white blood cell linked to inflammation) or allergic triggers. Allergy tests may also be recommended if symptoms are suspected to be allergy-related.
Adults often present with long-standing symptoms, and tests may need to rule out conditions such as COPD (chronic obstructive pulmonary disease). Spirometry, peak flow monitoring, and blood tests are the most common first-line investigations.
If you’re over 40 and experiencing breathing issues for the first time, your doctor may also suggest chest X-rays or additional screening to exclude other causes.
Asthma is common in children, but diagnosing it can be tricky as younger children may struggle with spirometry.
For children, doctors often use:
Blood tests may be suggested to check for allergies, as asthma in children is often linked to allergic conditions like eczema or hay fever.
If you’re concerned about your child’s breathing, booking a consultation with a private GP can help speed up referrals and access to paediatric specialists.
Once asthma is confirmed, your doctor will usually:
At Private Medical Clinic, we also offer allergy testing and blood tests that can support your asthma management.
Not on its own. Blood tests for asthma can measure inflammation or allergy markers, but they are usually combined with breathing tests for an accurate diagnosis.
The most common and quick method is spirometry, which measures lung function. Peak flow monitoring over time may also be used for a clearer picture.
Parents can monitor symptoms, keep a diary, and use a peak flow meter if recommended by a doctor. But diagnosis should always be confirmed by a healthcare professional.
Yes, mild asthma may be missed for years, especially if symptoms are mistaken for allergies, colds, or being unfit. That’s why proper testing is important.
Yes, especially if you want faster access to testing, blood work, and referrals. At Private Medical Clinic, we offer same-day appointments and can arrange specialist investigations quickly.
Asthma testing combines medical history, lung function tests, and sometimes blood tests for asthma or allergies. Whether you’re searching for how to test for asthma, the process is safe, straightforward, and essential for long-term health.
If you’re worried about your breathing—or your child’s—book a consultation at the Private Medical Clinic today. Our experienced GPs can help arrange tests, provide advice, and support you every step of the way.
Dr. Ibrahim Mutlib (BMBS, BMedSci) is an experienced GP with specialist interests in mental health, gastrointestinal health, and respiratory medicine. A clinical leader and published author, he is passionate about innovative, patient-centred care that supports both physical and emotional wellbeing.
