Nudge Letters Slash Unnecessary Pathology Testing by Over 30%

A federal government-funded study published in The Lancet found that audit and feedback letters sent to Australian general practitioners (GPs) who were high requesters of certain pathology tests led to a reduction in test orders.

The letters, which informed GPs they were in the top percentile for ordering specific tests, resulted in a 36% reduction over the following six months and a 32% reduction sustained at 12 months.

Study Methodology

The study targeted 5,339 GPs whose requesting patterns for specific pathology test combinations were above the 90th percentile in 2019–21. The intervention focused on 10 common pathology batteries, including combinations of iron studies, thyroid stimulating hormone (TSH), vitamin D, vitamin B12, and thyroid function tests.

GPs qualified for the intervention if they were in the top 10% of requestors for these test batteries and also in the top 10% for at least two of the five individual tests in 2020/21. The authors noted that the GPs were not informed they were part of a study.

Intervention Details

The letters were sent in May 2022 and came from Australia's Chief Medical Officer. The study also tested variations of the intervention, including adding CPD-accredited education, cost information, or a visually appealing pamphlet. Researchers reported that none of these additions amplified the effect beyond the letter alone.

Impact and Statistics

The estimated reduction in test requests was 24,000 fewer requests in the first six months, rising to 42,000 fewer over 12 months.

Co-author Professor Rachelle Buchbinder described the intervention as "extremely successful, one of the largest effects ever observed in audit and feedback research."

Background Context

According to the study, over-requesting of pathology tests is a significant issue: up to 40% of tests are considered unnecessary. In 2022–23, 160 million pathology services were requested in Australia at a cost of $3.8 billion to Medicare.

The Department of Health, Disability and Ageing (DoHDA) has used similar nudge letters for semaglutide prescribing and Medicare Benefits Schedule (MBS) claims.

Statements

Professor Buchbinder stated that overtesting increases false positives, patient anxiety, and unnecessary follow-up tests, and wastes resources while generating avoidable carbon emissions.

Chair of the Royal Australian College of General Practitioners (RACGP) Expert Committee – Quality Care, Professor Mark Morgan, said the research shows "benefit in targeted audit and feedback but no added benefit from complicating the information."

A DoHDA spokesperson stated that the department "prefers education and engagement to achieve compliance."

Current Status

The government confirmed there are no current plans to re-run this specific project.