Category: Lab Tests and Imaging

Categories : COVID Lab Tests and ImagingTags :

New French COVID Variant Invisible to PCR Tests

On By ModernMedia

French authorities have announced the detection of a variant of SARS-CoV-2 in the northwestern region of Brittany that has escaped detection by standard polymerase chain reaction (PCR) tests.

Real-time PCR tests are considered to be the current gold standard for detection of SARS-CoV-2, and currently take 4-6h to yield a result. PCR tests make millions to billions of copies of a small sample of DNA to create a larger sample for analysis.

Eight carriers of the variant were identified using genomic sequencing among a cluster of 79 cases in the town of Lannion in the Côtes d’Armor on March 13th.

In a statement on Monday, the French health ministry said that according to initial analyses, the new variant did not appear more transmissible or cause more severe disease. However, on Tuesday, authorities said that this variant was able to escape detection in PCR tests is raising concern.

Belgian virologist and interfederal COVID spokesperson Steven Van Gucht clarified the situation, in that about eight individuals presented with standard coronavirus symptoms, “but the tests remained negative.”

The World Health Organization has labelled this new French COVID variant a ‘variant under investigation’ (VUI), of which there are many thousands currently being monitored, as opposed to more serious variants like the South African B.1.351 variant which is more transmissible and is a ‘variant of concern’ (VOC).

However, just because this variant escaped the PCR tests being used in that area does not mean that it necessarily can escape all of them, as laboratories vary in the tests that they perform.

According to Gucht, tests differ in the different parts of the virus they look for, and also test for at least two to three. “Usually, a good test does not depend on detecting one specific part. So, if there is a mutation in one part of the virus, that signal may be lost, but there is usually a second or third signal that will be found,” explained Gucht.

French authorities are setting up systems to monitor the spread of this variant, and are also putting measures in place to contain it.

Source: News-Medical.Net

Categories : Lab Tests and ImagingTags :

Retinal Images Could Provide Stroke and Dementia Warning

On By ModernMedia

In the future, images of the retina could warn of a person’s increased risk of stroke and dementia, making it possible to take preventive measures.

These findings come from preliminary research to be presented at the American Stroke Association’s International Stroke Conference 2021.

Retinopathy is damage to the retina from injury or disease, commonly associated with diabetes. People with severe retinopathy are more likely to have a diseased-looking brain on magnetic resonance imaging (MRI). Retinal tissue has the highest consumption of oxygen in the body, and is the most vulnerable to oxidative stress. Most causes of retinopathy involve damage to the retinal and choroidal circulatory systems.

Study Lead Author Michelle P  Lin, MD., MPH, Neurologist at Mayo Clinic explained:”The retina is a window to the brain. A retinal photo that shows a magnified look at the back of the eye, including the retina and optic nerve, is cheaper and faster to perform than an MRI, so we’re wondering if it might be a good screening tool to see who could benefit from a referral to a neurologist for a brain MRI.”

In addition to the ophthalmologist’s office, retinal photos could be taken by a smartphone camera or via a smartphone adapter, Lin said.

Researchers explored the association of retinopathy with stroke, dementia, and the risk of death in 5543 adults who had participated in the annual US National Health and Nutrition Examination Surveys (NHANES) from 2005 to 2008. Interviews were conducted with the participants on a number of aspects of their medical history and health behaviours. Additionally, they received a retinal scan photo to look for signs of retinopathy.

Compared with participants not diagnosed with retinopathy, those with retinopathy were more than twice as likely to have had a stroke. They were also  nearly 70% more likely to have dementia; and more likely to die within the next 10 years, with increasing severity of retinopathy conferring a higher risk of death. The odds were calculated after adjusting for risk factors such as age, hypertension, diabetes and smoking.

“If you have retinopathy, work closely with your primary care doctor to alter your vascular risk factors and ask to be screened for cognitive impairment. You may be referred to a neurologist for evaluation and possibly a brain MRI,” said Dr Lin, who is also an assistant professor of neurology at the Mayo Clinic College of Medicine.

Source: News-Medical.Net

Categories : Lab Tests and Imaging Neurodegenerative DiseasesTags :

A Non-invasive Parkinson’s Test Inspired by Scent

On By ModernMedia

A  skin swab test has been developed for Parkinson’s disease, based on biomarker analysis of sebum, the oils that protect the skin – and it has a surprising inspiration. 

This comes about after the remarkable discovery of a woman’s ability to detect a certain smell in people who had the disease. 

Joy Milne, a retired nurse, noticed a “musky” scent on her husband years before he was diagnosed with Parkinson’s disease. A series of tests showed that she could detect the presence of Parkinson’s disease in people with 100% based on smell alone, prompting research which isolated the compounds she was smelling: higher concentrations of hippuric acid, eicosane, and octadecanal.

In order to exploit these biomarkers, researchers developed a mass spectrometry test to pick up their levels in sebum obtained with skin swabs. This has proved to be around 80% accurate.

Prof Perdita Barran said: “We believe that our results are an extremely encouraging step towards tests that could be used to help diagnose and monitor Parkinson’s.

“Not only is the test quick, simple and painless but it should also be extremely cost-effective because it uses existing technology that is already widely available.

“We are now looking to take our findings forwards to refine the test to improve accuracy even further and to take steps towards making this a test that can be used in the NHS and to develop more precise diagnostics and better treatment for this debilitating condition.”

This new test with its high reliability could help the diagnosis of Parkinson’s disease, which can be easily missed, especially in the early stages.
Daxa Kalayci, 56, was misdiagnosed several times over four years before finally finding out she had Parkinson’s in 2019.

“I was misdiagnosed with anxiety, stress-related tremors and told that my problems stemmed from going through the menopause,” she said.

“Despite my diagnosis eventually being confirmed… a quick and simple diagnostic test for Parkinson’s would have given me the chance to start my treatment earlier and enjoy life a lot more.

“But instead, I lost so many years not being able to pursue a career as a paramedic or go back to nursing.

“This test could be a game-changer for people living with Parkinson’s and searching for answers, like I was.”

Source: BBC News

Categories : COVID Lab Tests and ImagingTags :

Siemens COVID Antigen Test Kit Receives German Approval

On By ModernMedia

Siemens Healthineers announced on Wednesday that their antigen self-test kit, which uses samples from a nasal swab, has received limited special approval from the Federal Office for Drugs and Medical Devices (BfArM) for self-use by laypeople in Germany. The regular conformity assessment procedure for the standardised ‘CE‘ mark was also initiated for personal use by laypeople.

“With the provision of the COVID-19 antigen rapid test for possible use by laypeople in Germany, we are breaking new ground and are thus continuing to fulfill our social responsibility to support a return to normal social life,” said Bernd Ohnesorge, Head of Europe, Middle East, and Africa Regions, Siemens Healthineers

The practicability of the kit was confirmed by a study in which 50 participants without medical training personally carried out the test by following the instructions for use. The test already has a CE mark for use by specialist groups for taking samples in the nose.

“The CLINITEST COVID-19 Antigen Self-Test offers users a high degree of flexibility in performing the test with very good quality results,” said Christoph Pedain, Head of Point of Care Diagnostics at Siemens Healthineers.

Siemens’ COVID-19 Antigen Self-Test takes 15 minutes to give a result, using samples taken from both nostrils using a swab. The swab is then washed out in a reagent, which detaches a specific protein from the surface of the virus. The resulting liquid is dripped into a recess in the test cassette.

The test liquid migrates into the field of view of the cassette within 15 minutes, becoming visible as a line. The position and number of lines indicate as to whether there is a positive or negative test result, or whether there was a problem, necessitating a repeat of the test.

In the instructions, the tester is shown the steps to achieve a test result, including instructions on how to proceed according to the test result. A negative test result does not exempt the user from any local COVID regulations. Currently, the test kit is also available in the UK.

Source: Siemens

Categories : COVID Lab Tests and ImagingTags :

COVID Variants May Increase False Negative Results, FDA Warns

On By ModernMedia

The UK variant of the SARS-CoV-2 virus, known as B.1.1.7 could affect the accuracy of certain molecular COVID tests, causing increased false negative results, the US Food and Drug Administration (FDA) has warned.

A false negative from the UK variant could happen if the variant’s mutation happened to be in a part of the virus’ genome that was assessed by that test. However, genetic tests that target multiple parts of the virus genome are less likely to be affected by the new variants, the FDA advises.

Although the possibility of false negative results are to be expected from almost all tests, the effect of the COVID variants could impact the ability to properly monitor the disease, as well as complicating diagnosis.  

The FDA issued an alert on Friday, saying that they monitor tests which have received an Emergency Use Authorisation (EUA). They highlight three tests as being affected, with potentially less sensitivity to the mutations:

  • Accula SARS-Cov-2 Test, from Mesa Biotech
  • TaqPath COVID-19 Combo Kit, from Thermo Fisher Scientific)
  • Linea COVID-19 Assay Kit, from Applied DNA Sciences

However, the warning for Accula test was a result of “an abundance of caution”, and the latter two assess multiple genetic targets, so they are not likely to be impacted. The FDA issued recommendations for the users of these devices.The FDA’s warning was prompted by computer simulations showing reduced efficacy in certain tests for the virus variant.

In their press release, the FDA did not specifically mention whether any tests may be affected by mutations in the South African virus variant.

Source: MedPage Today

Categories : Cancer Lab Tests and ImagingTags :

New Multi-cancer Blood Test Offered by NHS

On By ModernMedia

A new blood test developed by the California-based Grail company tests for DNA methylation, and is supposedly able to screen for over 50 cancer types this way.

The NHS is to offer the test to 165 000 people from the middle of next year, with 140 000 screened through their medical records and the remaining 25 000 through referrals from suspected symptoms. It is hoped that widespread screening and early detection will drastically improve cancer survival rates, consequently easing pressure on healthcare services.

Lawrence Young, a professor of molecular oncology, at Warwick University, said the Galleri test was one of several novel blood tests being developed to spot cancer early on. “A publication from the Circulating Cell-free Genome Atlas consortium examining the Galleri test in 6 689 participants has generated very encouraging results in more than 50 different cancers at different stages of development.”

However, there was disagreement from some cancer experts regarding Galleri’s  potential effectiveness. Paul Pharoah, a professor of cancer epidemiology, at Cambridge University, said that it was premature for the NHS to embrace an unproven test. He said, “The Galleri blood test is a test that might be able to detect cancer in the blood in individuals with early cancer, though the evidence that it does this effectively is weak,” Pharoah said. According to him, only a single published paper on the tests was available, wherein they detected a mere 25% of early-stage cancers and under half of late-stage cases.

Source: The Guardian

Categories : Lab Tests and ImagingTags :

New Minimally Invasive Way to Sample Interstitial Fluid

On By ModernMedia

A new method to extract dermal interstitial fluid (ISF) for analysis has been reported. ISF contains a large number of biomarkers which can be used for diagnosis.

The minimally invasive process uses an array of almost invisibly small needles, approximately one quarter of a millimetre long. These were pressed to the skin and suction applied. Care needed to be taken so that the needles did not poke into microcapillaries in the skin and thus contaminate the sample with blood. 

Blood is often used for testing, comprising some 6% of the human body’s fluids, but some 10 000 compounds are found in ISF and 12% of the chemicals are not found in the blood. With the technique, the researchers were also able to measure the effects of glucose and caffeine, which are dynamically active. Traditional methods used to extract are quite invasive; using a needle to withdraw ISF from a vacuum-induced blister, or surgically inserting tubes underneath the skin.

Although the procedure is still time consuming, taking some 20 minutes per patient, it compares to the ~40 minutes required to form a vacuum blister in some ISF sampling protocols. The small needle injuries healed within a day, and there was minimal irritation.

This form of testing could have many applications, such as skin toxicological studies and monitoring glucose levels.

The journal article has been published in Science Translational Medicine.

Source: News-Medical.Net

Categories : Lab Tests and ImagingTags :

Simple New Method to Improve Time Release of Drugs

On By ModernMedia

Researchers have developed a new method to measure the release of drugs over time, using a simple method.

OxyContin, containing the opiate oxycodone, was intended to offer 12-hour pain relief. Instead, in some patients it dissolved much more quickly, causing them to take it more frequently and ultimately become addicted. But assessing how a drug dissolves in the body is surprisingly tricky. Drug dissolution has to be measured under laboratory conditions that come as close as possible to mimicking what happens in the body.

Corresponding author William Grover, associate professor of bioengineering at the Marlan and Rosemary Bourns College of Engineering explains: “We directly measured dissolution profiles of single drug granules, which are the little spheres you see when you open up a capsule. We accomplished this using a vibrating tube sensor, which is just a piece of glass tubing bent in the shape of a tuning fork.”

Many factors influence the way a drug is dissolved in the body, such as the chemical composition and pH of the fluid, the patient’s sex and their metabolism. Meals taken also have a strong impact: taking a fatty meal increases the amount of oxycodone released from OxyContin by 25%.

Pharmaceutical companies simulate these conditions in test vessels to build a profile of how the drug works over time, but this has its drawbacks. The position of tablets in the vessels can affect dissolution rates; equipment can become clogged; the process is very time-consuming and they only provide brief snapshots over time.

The new approach takes a radically different approach, measuring the mass of a drug granule as it dissolves. This is accomplished by changes in the resonant frequency, which can be measured over time instead of being sampled.

Using the technique on three proton-pump inhibitors, the researchers found considerable variations between name-brand and generic formulations of the drugs, affecting the rate at which the drugs are absorbed by patients.

“Our technique is much cheaper and easier to perform than conventional methods, and that enables pharmaceutical companies to do more tests in a wider variety of conditions,” said Grover. “We can also easily see differences in dissolution between individual particles in a drug. That should help pharmaceutical companies improve and monitor the consistency of their manufacturing processes.”

Source: Medical Xpress