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LAST week saw the release of a report which examined the economic value of pathology testing.
This report is welcome as the contribution of pathology to health care is often hidden, with much of the activity taking place away from the patient care setting. Some of the findings of the report are described below:
- Pathology is ubiquitous throughout the health system as a diagnostic tool and to monitor patient progress, informing treatment decisions
- Half the Australian population had a pathology test in the last 12 months and the number of tests being ordered by GPs has risen significantly in recent years.
- This rise does not indicate over-testing; the report showed that at least a third of the rise in test requests is from doctors seeking to prevent or minimise the impact of disease.
In order to demonstrate the value of pathology, the report focused on three specific areas: diabetes, chest pain presentations to emergency departments, and treatment for colorectal cancer.
As a chemical pathologist with a special interest in diabetes, I cannot stress the importance of pathology testing strongly enough. Quite simply, it is central to controlling diabetes and other chronic diseases. Managing diabetes without pathology would be like trying to drive a car without a steering wheel.
According to the report, diabetes related testing accounts for 10.5% of the growth in requesting from general practice and 6% of all GP orders for pathology.
Figures from Diabetes Australia show that 1.7 million Australians have diabetes. This includes an estimated 500 000 people who are currently undiagnosed. The number of Australians with diabetes is forecast to rise to 3.5 million within 17 years.
Figures in the Economic value of pathology report show that diabetes complications account for 14% of preventable hospitalisations, 67% of Australian adults with diabetes have high blood pressure, and 68% of adults with diabetes die of heart disease or stroke.
Preventing diabetes or delaying its onset is a key concern for the Australian health care system.
Pathology testing forms the basis of type 2 diabetes prevention programs, which can save between $2600 and $5300 per life year.
Unmanaged diabetes could be likened to reckless driving, where the consequences and costs can be serious.
- Related: MJA InSight — Graham Jones: Pathology power
- Related: MJA — Guidance concerning the use of glycated haemoglobin (HbA1c) for the diagnosis of diabetes mellitus
However, paying attention to the “speedometer” of regular HbA1c test results and acting on them can minimise the risk of accidents. A small sustained decrease in blood glucose levels can reduce the cumulative incidence over 5 years in end-stage kidney disease by 40%, amputation by 21%, advanced eye disease by 43%, and heart attack by 16%.
These details included in the report demonstrate not only the economic value of pathology testing but the benefit to patients too.
Pathology can be easily misunderstood or underestimated by the general public, as most people will never meet a pathology professional or even receive their pathology report first hand.
The examples used in the report attempt to show the breadth of pathology testing and how it fits in to medical care.
Diabetes diagnosis and management may often be part of general practice care, but emergency departments also rely on pathology. The report details the benefits of troponin testing in diagnosing heart attacks quickly and allowing discharge of patients with less serious conditions.
Pathology’s role in cancer care is also discussed; the report notes the use of KRAS and RAS genetic tests in colorectal cancer that determine which expensive epidermal growth factor receptor inhibitor drugs will work for which patient.
Health professionals know the importance of pathology and the enormous wealth of information it provides, but among patients, pathology’s role at the forefront of research, targeted treatment and diagnosing and understanding disease is still somewhat hidden. The economic value of pathology report could provide the jump-start needed for more public visibility.
Associate Professor Graham Jones is an ambassador for Pathology Awareness Australia and a pathologist at St Vincent’s Hospital, Sydney
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Thank you for the article. Of course pathology testing is intrinsic to modern medicine, but we must also consider the consequences of over-use and overdiagnosis. One of the greatest issues is the use of a diagnostic test in a low-prevalance population, resulting in a large percentage of false positive results. Chasing these can cause real harm, which needs to be balanced against the harms of underdiagnosing.
CHest pain work-ups in EDs are an important source of over-diagnosis. Diagnosis needs to consider history, examination AND tests, not just levels of high-sensitivity Troponin. Well people with normal ECGs are a group with a relatively low risk. In addition, the detection of troponin in the blood is not specific to acute coronary occlusion – it merely reflects hypoxic strain on cardiomyocytes, which can be part of any systemic illness. The advent of high sensitivity troponin has converted global poor perfusion states into a category of myocadial infarction – totally misunderstanding the pathophysiology.
D-dimer measurement is another case in point – with very low specificity. A positive D-dimer in a well person can lead to a cascade of testing for a condition for which the patient is not at risk.
Any discussion of use of pathology testing should come with a handboook on Bayesian logic. The accuracy of a test in making a correct diagnosis is dependant on the pre-test probability of the disease.