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Rapid Diagnostics Test Can Detect Asymptomatic Malaria Cases

On By ModernMedia

Researchers have adapted a rapid diagnostic technology that is able to identify undetected cases of malaria, helping tackle the spread of disease.

A diagram showing how the Dragonfly technology works (Credit: ProtonDx)

A team of scientists from Imperial College London, the MRC Unit The Gambia, the Clinical Research Unit of Nanoro in Burkina Faso, ProtonDx Ltd, and the NIHR Global Health Research Group have developed and validated a low-cost, point-of-care diagnostic that can rapidly detect low levels of malaria from a finger prick.

The test, called Dragonfly, relies on technology originally created at Imperial and its spinout ProtonDx. The technology allows users to diagnose malaria with high accuracy, without the need for extensive laboratory equipment or infrastructure. Results can be delivered in as little as 45 minutes, and the test is sensitive enough to detect even the lowest levels of malaria parasites in the blood – meaning that people without symptoms of malaria can still be identified.

Malaria is one of the leading causes of preventable deaths worldwide, with around 95% of all deaths occurring in Africa. Asymptomatic infections are a major driver of ongoing transmission, as individuals who carry the disease without showing symptoms do not seek medical treatment. Mosquitos feeding on blood from people without malaria symptoms can still deliver the malaria parasite to other people when they take their next blood meal. The new technology offers hope for combatting this potential spread of infection, by offering a way to identify previously undetectable malaria cases rapidly and on the ground in countries which are most affected by malaria.

The findings, published in Nature Communications, have significant global health implications as this field-deployable molecular diagnostic method offers a sensitive, scalable solution to support test-and-treat strategies for malaria elimination across Africa.

Professor Aubrey Cunnington, from Imperial’s Department of Infectious Disease and Co-Lead of the NIHR Global Health Research Group with Professor Halidou Tinto (from IRSS, Burkina Faso), said: “This is the first time that a diagnostic test for use outside of a laboratory setting has proven sensitive enough to detect low level malaria parasite infections in people who don’t have any symptoms.

“These people are the main source of malaria transmission, and in countries trying to eliminate malaria, there has long been interest in trying to detect these asymptomatically infected people with a screening test performed in their communities, and then giving treatment to those who are positive.

“Until now, no test has been able to detect enough of these infected people to make this a viable proposition, but the Dragonfly test now makes this possible.”

Detecting the undetectable

By collaboratively working as part of the NIHR Global Health Research Group, scientists were able to develop and test this new technology with the help of researchers in the regions affected most by malaria.

Almost 700 blood samples were collected from the community in The Gambia and Burkina Faso to assess the Dragonfly test’s accuracy against gold standard PCR testing and other common methods of testing, including expert microscopy and rapid diagnostic test (e.g., lateral flow immunoassay).

It was found that the Dragonfly tool could detect >95% of all malaria parasite infections, including 95% detection of those where the numbers of parasites were too low to be detected by looking at blood under a microscope.

Although Dragonfly is currently used as a research-used-only device, important progress is being made to understand the potential cost of a final manufactured version – especially when deployed at scale – a critical factor for effective deployment in sub-Saharan Africa. The team is already working closely with the Africa Centres for Disease Control and Prevention to explore opportunities with local manufacturers in the region, ensuring that production and scale-up can be rooted in local capacity. Future studies will also need to assess the robustness of the tool in community settings which are less connected to laboratory facilities.

Dr Jesus Rodriguez-Manzano, last author and technology development lead, from the Department of Infectious Disease, said “This research would not have been possible without the collaborative nature and all the organisations who took part in this study. The technology delivered through this work represents a game changer for malaria control efforts.”

The testing equipment

In the Dragonfly testing process, a capillary blood sample obtained from a simple finger prick is processed in around 10 minutes, without the need for specialised laboratory equipment, to extract high-purity nucleic acids from malaria parasites. The prepared sample is then placed into a detection panel, which is inserted into a portable heater.

After a 30-minute incubation at a constant temperature, results can be read visually using a colour chart: a pink reaction indicates a negative result, while a yellow reaction confirms malaria infection.

The Dragonfly can be manufactured at a fraction of the cost of other platforms, is compact enough to fit into a backpack, and can operate on batteries, an important feature for bringing the tool directly to communities without requiring additional specialised equipment. Testing can be carried out by most people without extensive training, meaning that healthcare providers or scientists do not need to be present for its use.

Source: Imperial College London

Categories : Cancer Lab Tests and ImagingTags :

Test Detects Cancers in the Bloodstream Three Years Prior to Diagnosis

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Photo by Hush Naidoo on Unsplash

Genetic material shed by tumours can be detected in the bloodstream three years prior to cancer diagnosis, according to a study led by investigators at Johns Hopkins.

The study, partly funded by the National Institutes of Health, was published in Cancer Discovery.

Investigators were surprised they could detect cancer-derived mutations in the blood so much earlier, says lead study author Yuxuan Wang, MD, PhD, an assistant professor of oncology at the Johns Hopkins University School of Medicine. “Three years earlier provides time for intervention. The tumours are likely to be much less advanced and more likely to be curable.”

To determine how early cancers could be detected prior to clinical signs or symptoms, Wang and colleagues assessed plasma samples that were collected for the Atherosclerosis Risk in Communities (ARIC) study, a large National Institutes of Health-funded study to investigate risk factors for heart attack, stroke, heart failure and other cardiovascular diseases. They used highly accurate and sensitive sequencing techniques to analyse blood samples from 26 participants in the ARIC study who were diagnosed with cancer within six months after sample collection, and 26 from similar participants who were not diagnosed with cancer.

At the time of blood sample collection, eight of these 52 participants scored positively on a multicancer early detection (MCED) laboratory test. All eight were diagnosed within four months following blood collection. For six of the eight individuals, investigators also were able to assess additional blood samples collected 3.1–3.5 years prior to diagnosis, and in four of these cases, tumour-derived mutations could also be identified in samples taken at the earlier timepoint.

“This study shows the promise of MCED tests in detecting cancers very early, and sets the benchmark sensitivities required for their success,” says Bert Vogelstein, MD, Clayton Professor of Oncology, co-director of the Ludwig Center at Johns Hopkins and a senior author on the study.

“Detecting cancers years before their clinical diagnosis could help provide management with a more favourable outcome,” adds Nickolas Papadopoulos, PhD, professor of oncology, Ludwig Center investigator and senior author of the study. “Of course, we need to determine the appropriate clinical follow-up after a positive test for such cancers.”

Source: Johns Hopkins Medicine

Categories : Hospitals Lab Tests and ImagingTags :

Patients ‘Don’t Need to be Checked for Everything’, Recommendation Says

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Blood samples
Photo by National Cancer Institute on Unsplash

Commonly ordered tests can provide early warning of underlying disease, but could also create unnecessary risks of false positive results, provoking anxiety in the patient, wasted time and money and risks of invasive testing.

Therefore, to combat commonly ordered – but not always necessary – procedures and tests, the Society of General Internal Medicine (SGIM) on Tuesday released its revised list of recommendations on five primary care procedures and tests that patients and physicians should question.

Northwestern University’s Dr Jeffrey A. Linder and David Liss, who have previously published research on the benefits of primary care checkups, helped revise the list.

For instance, the age-old idea of getting an annual physical exam with “routine blood tests” from a primary care doctor is a misconception because a person’s age and other risk factors should influence how frequently they should see their doctor, Linder said.

“We often have patients come in asking us to ‘check me for everything,’ but this is a potentially anxiety-provoking, dangerous thing for patients because the more testing we do, the more stuff we find, and the more we need to follow up,” said Linder, chief of the division of general internal medicine at Northwestern University Feinberg School of Medicine and a Northwestern Medicine physician. “In someone who is asymptomatic, an ‘abnormality’ is much more likely to be a false positive or of no clinical significance than for us to catch early disease.

“False positives can expose patients to all of the anxiety, costs, hassle and time commitment, and danger from sometimes invasive testing, with a very low likelihood that it is going to improve their health.”

This isn’t to say nobody should get a checkup every year. For instance, patients who have overdue preventive services, rarely see their primary care physician, have low self-rated health and/or are aged 65 or older should get an annual checkup, the scientists said.

The newly revised list is part of SGIM’s Choosing Wisely campaign, which is an initiative of the American Board of Internal Medicine Foundation. SGIM members originally selected the topics in 2013 and later updated the list in 2017.

The list generated controversy when it was first developed in 2013, recalls Linder.

“The list was widely misinterpreted as ‘specialty society says you don’t need to see your doctor,’ but that was not what it said,” Linder said.

Time and downstream financial costs also are issues of these commonly ordered but oftentimes unnecessary tests and procedures, Liss said.

“Patients and care teams often spend valuable time on low-value checkups that could have been devoted to high-need patients,” said Liss, research associate professor of general internal medicine at Feinberg. “There also is the overall increase in costs to the health system. And even if annual checkups are covered by most insurance, patients often have copays for services like blood draws and other diagnostic tests.”

The revised list was developed after months of careful consideration and review, using the most current evidence about management and treatment options. Linder and Liss served as ad hoc members of the SGIM’s Choosing Wisely Working Group.

Here are the five recommendations, based on a review of the most recent studies in the field:

  1. Don’t recommend daily home glucose monitoring in patients with Type 2 diabetes mellitus not using insulin.
  2. Don’t perform routine annual checkups unless patients are likely to benefit; the frequency of checkups should be based on individual risk factors and preferences. During checkups, don’t conduct comprehensive physical exams or routine lab testing.
  3. Don’t perform routine pre-operative testing before low-risk surgical procedures.
  4. Don’t recommend cancer screening in adults with life expectancy of less than 10 years.
  5. Don’t place, or leave in place, peripherally inserted central catheters for patient or provider convenience.

Source: Northwestern University

Categories : HospitalsTags :

Inpatient Blood Draws are Often Performed During Sleep Hours

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Blood sample being drawn
Photo by Hush Naidoo Jade Photography on Unsplash

The sleep of hospitalised patients may be often interrupted due to non-urgent blood draws, according to findings from a Yale study published in JAMA. This may be exacerbating sleep deprivation, and putting them at greater risk for health events later on.

In an analysis of more than 5 million non-urgent blood draws collected at Yale New Haven Hospital from 2016 to 2019, a team of researchers found that a high proportion of them occurred during a three-hour window in the early morning.

“We found that nearly four in 10 of total daily blood draws were performed between 4am and 7am,” said César Caraballo-Cordovez, MD, a postdoctoral associate at Yale Center for Outcomes Research and Evaluation (CORE) and co-lead author of the study. “Importantly, we found that this occurred across patients with different sociodemographic characteristics, including older individuals who are at highest risk of adverse health events from sleep deprivation.”

Although early morning blood draws are often considered necessary to inform decisions during morning medical rounds, the authors suggest that sleep interruptions may increase the risk of delirium and other adverse events. “Patients who were recently hospitalised experience a period of generalised risk for myriad adverse health events, a condition named posthospital syndrome,” added Dr Caraballo-Cordovez. “The stress that patients experience during the hospitalisation – including stress from sleep deprivation – is a key contributor to this period of increased risk.”

“This is not an issue at just one hospital,” said Harlan M. Krumholz, MD, SM, professor of medicine and public health at Yale and CORE director. “Our findings reflect an aspect of how inpatient hospital care is being delivered in modern medicine. A more patient-centered care would limit nonurgent tests during sleep hours. However, these early morning blood draws are often considered necessary to make decisions during rounds.”

“We need to re-design our process to protect patients’ sleep, but major changes in our practice must be informed by solid studies that demonstrate the efficacy of strategies to do so without untoward effects,” added Krumholz.

Source: Yale School of Medicine

Categories : Lab Tests and ImagingTags :

Shortage of Blood Test Tubes Prompts Saving Efforts

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Blood sample being drawn
Photo by Hush Naidoo Jade Photography on Unsplash

A pandemic-related shortage of a mundane item, ‘blue top’ blood test tubes used toollect blood samples from patients, has caused headaches for health systems worldwide.

But it may also have a silver lining: A lesson in how to reduce unneeded medical tests, whether or not there’s a shortage, according to a new study published in JAMA Internal Medicine.

The shortage gave researchers a chance to see if alerting doctors at the moment they’re placing an order could encourage them to seek a test only when results will immediately affect care.

In the new study, an alert led to a nearly immediate 29% drop in orders for one common test. The reduced level persisted for months.

“This shows that small interventions can make a big difference, and suggests the potential for other types of low-value care to benefit from a similar intervention,” says lead author Madison Breeden, MD, who conducted the study during her year as chief resident of Quality and Patient Safety. She’s already exploring if the approach might reduce unnecessary antibiotic prescriptionse

Breeden and her colleagues describe what happened in spring 2021 when University of Michigan Health supply chain and pathology experts began worrying about a potential shortage of ‘blue top’ tubes. The pandemic had created very high demand for the chemical the tubes contain: sodium citrate, which stabilises blood samples until a laboratory team can analyse three blood clotting-related properties, called PT, INR and PTT.

After emailing all providers, U-M Health added a ‘best practices alert’ to doctors’ test-ordering electronic system. They could still order PT/INR/PTT tests, but were asked for “thoughtful restraint in reflexive ordering.”

The alert began popping up a month before the FDA issued an official shortage notice and the issue got widespread attention. The shortage continues today and has grown to other types of tests.

The researchers looked at what happened for six months after the alert began appearing at U-M Health, and compared it with data from six months before.

“There are very important reasons to order this test in some patients, for instance before an operation or when managing certain conditions and treatments,” Breeden explains. “But it may also be part of a standard order set that’s put in during an emergency department visit and continues to be ordered repeatedly after the patient is admitted to the hospital, even though the results won’t change their care.” For such patients, a one-time test might be indicated, but not repeated testing.

Busy doctors entering orders for tests don’t tend to think about the supplies and people power needed to carry out those tests, Breeden notes. In the face of a shortage, or of strong evidence that a test is often over-ordered, an alert could help prioritize the tests for those who need them most.

Canadian experts have actually flagged PT/INR/PTT tests as a target for reducing unnecessary care, through the Choosing Wisely program. So has the American Society for Clinical Laboratory Science, a medical professional group.