What is a key diagnostic evaluation tool for suspected occupational asthma?

The key diagnostic evaluation tool for suspected occupational asthma is the use of serial measurements of peak expiratory flow rates (PEFR) at work and away from work. This method is particularly effective for determining whether exposure to workplace allergens or irritants is affecting a person's lung function.

By measuring PEFR at different times—specifically, during work hours and after leaving the workplace—healthcare providers can identify patterns in the patient's respiratory function that correspond to their work environment. A significant decline in PEFR during the workday, followed by improvement when away from work, strongly suggests that the asthma is related to occupational exposure.

This approach allows for a more accurate assessment of the impact of occupational factors on asthma symptoms, as opposed to relying solely on spirometry tests, which provide a snapshot of lung function but may not capture the fluctuations occurring due to specific exposures. Skin prick tests and chest X-rays are useful in diagnosing and monitoring asthma and other conditions, but they do not assess the occupational triggers that are crucial in cases of suspected occupational asthma. Thus, serial measurements of PEFR stand out as the most relevant tool in this context.