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Diagnostics Pipeline: Testing for Intestinal Parasites Takes Step Forward

by Ron Shinkman | Nov 25, 2024 | Clinical Diagnostics Insider, FDA-dtet

The EasyScreen assay received 510(k) clearance from the Food and Drug Administration earlier this year–but with a catch

Flat, abstract illustration of the human gut with microbes and parasites. — iStock, DrAfter123

Molecular testing over the past decade has primarily focused on genetic components of diseases and rapid diagnoses of infections. However, a new assay recently introduced to the United States by an Australian-based company is focused on an ever-present but often under-the-radar medical issue: intestinal parasites.

The test developed by Genetic Signatures is called EasyScreen^™. It can detect the eight most common gastrointestinal parasites in a single test from a single sample. The U.S. Food and Drug Administration (FDA) granted a 510(k) approval for the test in June.¹ However, a senior executive with the company noted that recent changes in FDA regulations means the assay must be processed using only Genetic Signatures’ own automated workflow—which includes sample extraction and multiplex PCR—or it reverts to a laboratory-developed test.

Intestinal parasites: a worldwide problem

Intestinal parasites are a distinct menace to humans. According to the press release announcing EasyScreen’s FDA approval, about 3.5 billion people–nearly half the global population–have supposedly been infected by a parasite, and these infections kill as many as 200,000 people a year.¹ However, there is no firm data attached to these numbers, as numerous academic studies have cited figures in other published studies.²

The World Health Organization did acknowledge in a 2023 bulletin that about 1.5 billion humans are infected with helminths, parasites transmitted from the soil. Such infections are commonplace in countries with poor access to clean water and hygiene. They are particularly prevalent in sub-Saharan Africa, China, South America, and Asia.³

Yet intestinal parasites are a distinct problem even in developed countries like the United States. According to Genetic Signatures, up to 65 million Americans are infected with intestinal parasites. Common parasites in the US include ascaris, hookworms, pinworms, and giardia, which is a microscopic protozoan, according to the Cleveland Clinic.⁴ According to Genetic Signatures, only about 15 percent of Americans who have parasites have been diagnosed.¹ Many get these parasites from contaminated food or surfaces, or by traveling to developing countries where parasites are more prevalent. The lack of a firm diagnosis can lead to complications such as malnutrition, impaired cognitive function, and even damage to vital organs such as the liver, lungs, or brain.

One of the most prominent victims of an apparent intestinal parasite is Robert F. Kennedy, Jr., whose brain was infiltrated by a suspected tapeworm from ingesting contaminated pork during an overseas trip. The worm caused brain fogginess so severe that a tumor was initially suspected.⁵ Kennedy is slated to head the U.S. Department of Health and Human Services—which includes the FDA—starting in early 2025.

Travel within the US can also bring risks from intestinal parasites. Genetic Signatures presses its argument for more effective testing in the US with a testimonial video from a patient who contracted giardia from drinking contaminated water while on a domestic business trip. He had been diagnosed with a salmonella infection for nearly three months before the real cause was determined. During that time, the patient underwent several rounds of unnecessary treatment with antibiotics. Genetic Signatures says its test can help avoid such misdiagnoses.⁶

Complexities of current tests

Testing for intestinal parasites is also complex. It typically relies on microscopy, which is an exacting and time-consuming process.

Moreover, the current testing regime for intestinal parasites has been haphazard at best. According to a recently published study in the academic journal Diagnostics, “false-positive or false-negative results are a problem facing many tests. Available tests have different sensitivities and specificities. Therefore, especially in doubtful situations, tests for the presence of the pathogen should be performed using various available methods. It is important that the methods used make it possible to distinguish an active infection from a past infection.”⁷

A recent editorial in the International Journal of Molecular Sciences also warned that testing protocols are far from optimal:

“There is still a lack of effective methods for detecting many parasites and for diagnosing and treating parasitoses and their related symptoms, such as allergic reactions and pathogen transmission,” the editorial noted. “There is also a need to improve and develop parasitological monitoring and forecasting methods in response to local and global environmental changes, such as climate change, which often expand the range of the host and thus the parasite.”⁸

How the test works

The EasyScreen assay relies on a single stool sample, according to Ron Gonzales, vice president of Genetic Signatures’ North American operations. He said that is “a vast improvement over other methods that require three samples from a patient over 10 days, or other molecular tests with half of the parasite targets.”

Turnaround can also be performed in a single day, which is a rarity for microscopy-based assays. Moreover, EasyScreen retails for just $95. However, if the sample is not processed on the EasyScreen platform, the assay becomes a laboratory-developed test under current FDA regulations, Gonzales observed.

“It’s not prohibited, but it is more work in validation and documentation for the laboratory performing the test,” he said.

Thoughts on LDTs

Regarding the current battle between laboratories and the FDA’s move to regulate LDTs, Gonzales conceded that the agency “has laid out a solid argument regarding their decision to regulate LDTs. However, the current FDA infrastructure is not equipped to handle the review of the many LDTs that are in the marketplace and are medically necessary. I believe that over the next 12 to 24 months the industry and the FDA will come to some compromises that will appease everyone.”

Meanwhile, having the EasyScreen test and platform available “provides a solution for protozoal testing while obviating the need for laboratories to manage and maintain an LDT within the future framework of the FDA,” said Marc Couturier, head of clinical operations for clinical microbiology and immunology for ARUP Laboratories, in a statement issued by Genetic Signatures.¹

Gonzales noted that Genetic Signatures has had sales, clinical, and scientific and tech support staff based in the United States for the past several years that have been working on sales of the test and platform, primarily to hospitals.

“The vast majority of customers want to bring in our entire system,” he said.