ONLY LIMIT IS IMAGINATION Covid was the spur that has taken the diagnostic testing industry in new directions and to new heights of achievement, says IVOR CAMPBELL
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ntil recently the only group of people likely to routinely come across a lateral flow test were women who wanted to know if they were pregnant in a hurry. Since Covid, such tests have become part of our everyday lives and the fabled passenger on the Clapham omnibus has suddenly become an expert in everything from antibodies and sandwich assays to dipstick formats. Despite concerns about the reliability of some tests, results have improved and the ease and speed with which self-testing is now routinely done has given diagnostics companies a valuable insight into the future market potential of rapid, point-of-care testing. The popularisation of testing has shone an unprecedented spotlight on the diagnostics industry as well as gaining the attention of investors. Forward planning groups have been hastily assembled to anticipate future demand and to develop
advanced stage technologies that are ripe for commercialisation. The benefit of lateral flow assays (LFAs) is in their speed, simplicity, low cost and robustness. Stored at room temperature, they can have a shelf life of several years. Billions of test strips are manufactured globally every year for point of care testing to diagnose a range of diseases and conditions, including sexually transmitted infections (STIs), malaria, tuberculosis and hepatitis. They are also used to test for pregnancy and fertility, cardiac markers, cholesterol/lipids, drug abuse, food safety drug abuse and veterinary diagnostics, among others. However, they can stop short when it comes to reliability, as any woman who has had to do multiple pregnancy tests before arriving at a definitive result, will testify. Birmingham-based Linear Diagnostics is pioneering a new process that promises to combine the speed of lateral flow technology with a high level or reliability in the diagnosis of STIs,
particularly chlamydia and Gonorrhoea. Co-founders Professors Tim Dafforn and Professor Matthew Hicks (pictured inset) developed the method – known as linear dichroism – which works by detecting a shift in the plane of polarised light focused on detector molecules of bacteria. Different molecular recognition methods can be used on detector molecules to measure target analytes and antibodies and detect antigens or oligonucleotides to capture complementary target DNA sequences. Brendan Farrell, chairman of Linear Diagnostics – a spinout company from the University of Birmingham – said: “Current testing for STIs takes days and uses molecular technology which detects the genetic material of whatever it is you’re looking for. “It detects a specific genetic
sequence that is unique to that organism, whether it is chlamydia and Gonorrhoea. “We are using a process which is a very simple way of detecting various molecules floating around in a solution. It shines polarised light on a solution that contains certain bacteria molecules and, if they bind to a target, the flow gets disrupted.” The point-of-care test can be done in a hospital or clinic within 15 minutes using a portable, single-use disposable cassette and electronic reader, both developed by partner company, Cambridge-based Sagentia Innovation. Farrell said: “We decided to focus on sexually transmitted infections, which is a large and growing market and not very well served with rapid testing at the moment. “The spread of some of the STIs is quite rapid. People don’t take
precautions and there is a significant spread of the diseases. “We detect chlamydia and Gonorrhoea in a single sample of urine or a swab sample. Some people will go to the doctor and get a sample taken and then get nervous and they don’t come back for the result. They don’t get treated, because they don’t know the result. “With this test within 15 minutes, which is a reasonable waiting time for someone sitting in a waiting room, they will be called back and, if they are positive, they can be given a prescription on the spot.” Among the most ambitious advances in testing has been done done by the global health arm of Omega Diagnostics, based in Alva, Clackmannanshire. Its point-of-care Visitect CD4 Advanced Disease technology is a
rapid, semi-quantitative lateral flow assay that can diagnose HIV within minutes. It does so by detecting relevant proteins on the surface of patients’ CD4 cells – also known as T cells – which are the white blood cells that fight infection and play an important role in the immune system. The company hopes that faster, point -ofcare diagnosis of HIV can slow the spread of the disease in low to middle income countries, particularly in Africa Chief Executive Colin King said: “The World Health Organisation (WHO) has identified that there are
still around 1million people around the world dying of HIV every year. For the past few years, if you have tested positive for HIV you have been given anti-retroviral drugs. The WHO did a deal with several companies to try to drive down and eradicate HIV in those countries. “It has been successful in reducing deaths but what they have found is that casualty rate has plateaued and hasn’t dropped any lower than 1million deaths a year.”. He added: “A substantial proportion
of people dying are in the advanced stages of HIV disease. “Because their CD4 count is below 200, they are more likely to die from other diseases because their immune system is so compromised. “We are putting in place a programme that will screen high risk patients in these countries. “If their CD4 count is below 200, then they will be tested for other diseases, such as tuberculosis, cryptococcal, meningitis and Aspergillosis. There’s about half a dozen other tests that sit around this that are potentially fatal and most are easy to treat.” Ivor Campbell is Managing Director of Stirlingshire-based Snedden Campbell, a search company for the medical technology industry.