London (AFP) - More than one million people receiving treatment for asthma may have been wrongly diagnosed, a health watchdog warned Wednesday as it published new draft guidance for doctors on testing for the condition.
Around 4.1 million people in Britain receive treatment for asthma but studies suggest that up to 30 percent do not show clear evidence of having the illness, the National Institute for Health and Care Excellence (NICE) said.
Some may have had asthma in the past but many were likely to have been given an incorrect diagnosis, the watchdog said.
The new guidelines for England, subject to consultation, recommend doctors use a range of clinical tests to diagnose the lung condition more accurately, as well as observing signs and symptoms.
Currently there is no "gold standard test" and diagnosis is mainly based on medical history, the report said.
Professor Mark Baker, director of clinical practice at NICE, said: "Accurate diagnosis of asthma has been a significant problem which means that people may be wrongly diagnosed or cases might be missed in others.
"Our aim with this guideline is to give clarity and set out the most clinical and cost-effective ways to diagnose and monitor asthma based on the best available evidence."
Spirometry, which assesses airflow, should be the first test used to reach a diagnosis, followed by further breath tests, the guidelines suggest.
Asthma is a common long-term condition that can cause coughing, wheezing and breathlessness. It affects 1.1m children and 4.3m adults in Britain and kills three people each day, according to the charity Asthma UK, which welcomed the guidelines.
"Asthma has many complex causes which is one of the reasons why it is sometimes difficult to get a definitive diagnosis," said Kay Boycott, chief executive at Asthma UK.
"It is also a highly variable condition that can change throughout someone's life or even week by week, meaning treatment can change over time.
"For anyone with an asthma diagnosis, it is vital they have the right medication and a plan to better manage their condition and any asthma attacks."