how your leftover pathology samples can be used for medical research

A doctor’s visit often ends with you leaving with a pathology request form in hand. The request form soon has you filling a sample pot, having blood drawn, or perhaps even a tissue biopsy taken.

After that, your sample goes to a clinical pathology lab to be analysed, in whichever manner the doctor requested. All this is done with the goal of getting to the bottom of the health issue you’re experiencing.

But after all the tests are done, what happens with the leftover sample? In most cases, leftover samples go in the waste bin, destined for incineration. Sometimes though, they may be used again for other purposes, including research.

Who can use my leftover samples?

The samples we’re talking about here cover the range of samples clinical labs receive in the normal course of their testing work. These include blood and its various components (including plasma and serum), urine, faeces, joint and spinal fluids, swabs (such as from the nose or a wound), and tissue samples from biopsies, among others.

Clinical pathology labs often use leftover samples to practise or check their testing methods and help ensure test accuracy. This type of use is a vital part of the quality assurance processes labs need to perform, and is not considered research.

Leftover samples can also be used by researchers from a range of agencies such as universities, research institutes or private companies.

They may use leftover samples for research activities such as trying out new ideas or conducting small-scale studies (more on this later). Companies that develop new or improved medical diagnostic tests can also use leftover samples to assess the efficacy of their test, generating data needed for regulatory approval.

What about informed consent?

If you’ve ever participated in a medical research project such as a clinical trial, you may be familiar with the concept of informed consent. In this process, you have the opportunity to learn about the study and what your participation involves, before you decide whether or not to participate.

So you may be surprised to learn using leftover samples for research purposes without your consent is permitted in most parts of Australia, and elsewhere. However, it’s only allowed under certain conditions.

In Australia, the National Health and Medical Research Council (NHMRC) offers guidance around the use of leftover pathology samples.

One of the conditions for using leftover samples without consent for research is that they were received and retained by an accredited pathology service. This helps ensure the samples were collected safely and properly, for a legitimate clinical reason, and that no additional burdens or risk of harm to the person who provided the sample will be created with their further use.

Another condition is anonymity: the leftover samples must be deidentified, and not easily able to be reidentified. This means they can only be used in research if the identity of the donor is not needed.

The decision to allow a particular research project to use leftover pathology samples is made by an independent human research ethics committee which includes consumers and independent experts. The committee evaluates the project and weighs up the risks and potential benefits before permitting an exemption to the need for informed consent.

Similar frameworks exist in the United States, the United Kingdom, India and elsewhere.

What research might be done on my leftover samples?

You might wonder how useful leftover samples are, particularly when they’re not linked to a person and their medical history. But these samples can still be a valuable resource, particularly for early-stage “discovery” research.

Research using leftover samples has helped our understanding of antibiotic resistance in a bacterium that causes stomach ulcers, Helicobacter pylori. It has helped us understand how malaria parasites, Plasmodium falciparum, damage red blood cells.

Leftover samples are also helping researchers identify better, less invasive ways to detect chronic diseases such as pulmonary fibrosis. And they’re allowing scientists to assess the prevalence of a variant in haemoglobin that can interfere with widely used diagnostic blood tests.

All of this can be done without your permission. The kinds of tests researchers do on leftover samples will not harm the person they were taken from in any way. However, using what would otherwise be discarded allows researchers to test a new method or treatment and avoid burdening people with providing fresh samples specifically for the research.

When considering questions of ethics, it could be argued not using these samples to derive maximum benefit is in fact unethical, because their potential is wasted. Using leftover samples also minimises the cost of preliminary studies, which are often funded by taxpayers.

Inconsistencies in policy

Despite NHMRC guidance, certain states and territories have their own legislation and guidelines which differ in important ways. For instance, in New South Wales, only pathology services may use leftover specimens for certain types of internal work. In all other cases consent must be obtained.

Ethical standards and their application in research are not static, and they evolve over time. As medical research continues to advance, so too will the frameworks that govern the use of leftover samples. Nonetheless, developing a nationally consistent approach on this issue would be ideal.

Striking a balance between ensuring ethical integrity and fostering scientific discovery is essential. With ongoing dialogue and oversight, leftover pathology samples will continue to play a crucial role in driving innovation and advances in health care, while respecting the privacy and rights of individuals.