Can pulmonary embolism be diagnosed incorrectly or missed? 

Pulmonary embolism is a medical condition where a blood clot blocks a blood vessel in the lung, which can lead to serious health complications if not identified promptly. Because its symptoms often overlap with many other common heart and lung conditions, the diagnostic process requires a high level of clinical suspicion and the use of structured testing pathways. This article explains how the diagnostic journey works in the UK and the measures healthcare professionals take to ensure a lung clot is correctly identified. 

What We’ll Discuss in This Article 

• Why pulmonary embolism is often called a “great masquerader” in medicine. 

• The common conditions that can mimic the symptoms of a lung clot. 

• How structured risk assessments like the Wells score reduce diagnostic errors. 

• The role of blood tests and imaging in confirming or ruling out a diagnosis. 

• Why some patients might require repeat testing if symptoms persist. 

• Emergency protocols for ensuring patient safety during the diagnostic phase. 

The challenges of diagnosing pulmonary embolism 

A pulmonary embolism can be difficult to diagnose because its primary symptoms, such as shortness of breath and chest pain, are also present in many other common illnesses. Doctors must carefully distinguish a blood clot from conditions like pneumonia, asthma, or even a heart attack, which is why a single symptom is rarely enough to confirm a diagnosis. In the UK, medical teams use a combination of patient history, physical examination, and specific diagnostic tools to navigate these similarities and reach an accurate conclusion. 

Conditions that mimic pulmonary embolism 

Several other medical issues can present with symptoms nearly identical to those of a pulmonary embolism, which can lead to initial diagnostic uncertainty. The NHS notes that pulmonary embolism symptoms like sudden shortness of breath and sharp chest pain are also typical of other lung problems or heart conditions. By performing tests such as chest X-rays and Electrocardiograms, doctors work to exclude these “mimics” before focusing on the blood vessels of the lungs. 

Condition	Overlapping Symptoms	Key Diagnostic Difference
Pneumonia	Shortness of breath, chest pain, cough.	Often accompanied by fever and changes on a chest X-ray.
Heart Attack	Chest pain, breathlessness, lightheadedness.	Usually identified by specific heart protein blood tests and ECG changes.
Asthma	Wheezing, breathlessness, chest tightness.	Often has a known history and responds to inhaler treatment.
Pleurisy	Sharp chest pain when breathing in.	Inflammation of the lung lining, often caused by viral infections.

How structured pathways prevent missed diagnoses 

To minimise the risk of a pulmonary embolism being missed, UK healthcare professionals follow strict clinical guidelines developed by NICE. These guidelines involve using a clinical prediction rule, such as the Wells score, to objectively calculate the probability of a clot based on a patient’s risk factors and physical signs. NICE guidance ensures that if a pulmonary embolism is considered likely, patients are moved quickly to definitive imaging like a CTPA scan. Using these standardised steps helps ensure that even when symptoms are vague, the possibility of a clot is systematically investigated. 

The role of follow-up and persistent symptoms 

In some cases, if initial tests are negative but a patient’s symptoms continue or worsen, doctors may need to reconsider the diagnosis or perform additional investigations. A negative D-dimer blood test is very reliable at ruling out a clot in low-risk patients, but it is not infallible. If a patient remains unwell, clinicians will look for other causes or may occasionally repeat certain assessments to ensure that a developing condition has not been overlooked during the first hospital visit. 

Ensuring accuracy through advanced imaging 

Advanced imaging scans, such as Computed Tomography Pulmonary Angiography, are highly accurate at detecting clots, but their effectiveness depends on the quality of the images and the timing of the scan. Factors such as a patient’s ability to hold their breath or the size of the clot can occasionally influence how clearly a blockage is seen. By using these detailed scans as a gold standard, medical teams in the UK aim to provide a definitive answer and initiate life-saving anticoagulant treatment as soon as a diagnosis is confirmed. 

Conclusion 

While pulmonary embolism can be challenging to identify due to its varied symptoms, the use of structured clinical pathways significantly reduces the likelihood of it being missed or misdiagnosed. Doctors rely on a combination of risk scores, blood tests, and advanced imaging to distinguish clots from other conditions. Maintaining a high level of clinical awareness is essential for patient safety and successful treatment. If you experience severe, sudden, or worsening symptoms, call 999 immediately. 

Authority Snapshot (E-E-A-T Block) 

This article was produced by the MyPatientAdvice Medical Content Team and reviewed by Dr. Stefan Petrov to provide clear, evidence-based information on the diagnostic process for pulmonary embolism. The content is strictly aligned with UK clinical standards, specifically the guidance provided by the NHS and NICE. This information is intended for public education and does not replace professional medical diagnosis or emergency care.