Patients see doctors in a white coat as professional and trustworthy but often mistake a female medic wearing one for a nurse or medical assistant, a study has found.

Female physicians are “unfairly judged based on appearance and attire, which affected patients’ perceptions of professionalism and competency”, according to a global review of the evidence around patients’ impressions of what doctors wear.

“Female physicians are often judged more on appearance than their male counterparts,” it said.

“The way female physicians dress significantly influences perceptions of competence and professionalism, highlighting the gendered expectations that patients hold.

“Even when male and female physicians wore identical attire, female physicians were still more likely to be misidentified as nurses or medical assistants.”

The researchers found that “gender-related perceptions of physician attire” existed across the 13 countries studied, including the US, India, Japan, China and Germany.

The paper, published in the journal BMJ Open, is based on an analysis of 32 previously published studies on perceptions of doctors’ clothing.

“The expectations regarding attire are often gendered, particularly affecting the recognition and respect given to female physicians,” the paper’s co-authors write.

Such behaviour is so widespread that hospitals and other healthcare providers should try to reduce bias among patients and “foster equitable perceptions” of male and female medics, they add.

The white coat has been a symbol of medical expertise for decades. Its association in patients’ minds with cleanliness and professionalism meant that “white medical coats became the standard attire for physicians worldwide in the 20th century”.

Until then, doctors had generally worn black clothing to reflect the seriousness of meetings with patients.

People receiving healthcare find the white coat reassuring, the study found.

“Regardless of gender, patients exhibited favourable attitudes towards physicians wearing white coats, perceiving the physicians as trustworthy, respectful, skilled, communicative and empathetic.”

The white coat is still widely used by doctors worldwide. However, it was banned in the UK in 2008, when the government decided that medics working in the NHS should follow a “bare below the elbows” approach to reduce their risk of spreading infections. The British Medical Association was unsure that evidence justified the change.

Despite patients’ preference for doctors wearing formal clothing, the Covid-19 pandemic made them more accepting of scrubs.

“Patients tended to feel more comfortable with physicians wearing scrubs after Covid-19 ceased. While the traditional white coat is seen as a symbol of professionalism and trust, patients have increasingly accepted scrubs, especially in emergency or high-risk settings,” the researchers found.

Globally, male doctors seem to enjoy another advantage in many patients’ minds as to what they wear.

“Patients’ perceptions of male physicians’ accessories have shown that details such as watches and glasses significantly impact professionalism and trustworthiness” and add to their perceived authority, the study found.