Peritoneal dialysis (PD) is a type of treatment to remove waste products from the blood for people with kidney failure. The treatment has many benefits compared to others, but it carries a greater risk of associated infections which can lead to peritonitis. Often people don’t realise they have an infection until they become unwell and are admitted to hospital for treatment. Tests for identifying a specific infection take a long time and so people with severe infection are often treated with broad spectrum antibiotics until the lab tests confirm the specific diagnosis. Researchers wanted to develop ways to diagnose peritonitis quicker, earlier, and at home, so that people can take the proper medication, avoid becoming unwell and needing admittance to hospital.
Supported by Health and Care Research Wales, the Medical Research Council, Kidney Research UK, the European Commission and the National Institute for Health Research, researchers at the WKRU led by Dr. Mattias Eberl worked with industry partner Mologic. The team utilised new understandings in ‘immune finger printing’ – the unique marks that bugs leave behind – to test the immune systems response to different microbes.
Normally to identify the cause of an infection involves taking a sample and growing the bugs in the laboratory. But this takes time, is not always reliable and if people have a serious acute infection they need treatment straight away. Instead the research team used our own highly complex and sensitive immune systems to identify two critical ‘biomarkers’ of infections in PD waste fluid using a ‘lateral flow immunoassay system’. Probably the most well know system which uses this testing type is the pregnancy test. This new test works in a similar way.
121 frozen samples of waste dialysate from PD users were tested:
- 66 samples from users clinically diagnosed with peritonitis.
- 55 samples from users without peritonitis.
The test gave a positive result for 65 of the 66 peritonitis samples (98.5% sensitivity), and a negative result for 52 of the 55 stable user samples (94.5% specificity). The data above was generated using Version 1 of the PERiPLEX test. A further study has been performed to demonstrate performance equivalence between Version 1 and Version 2. You can read all about the laboratory research here. https://orca.cf.ac.uk/93873/1/2195.full.pdf
Improved health and care for people living with kidney disease
PERiPLEX is a non-invasive home test that works in a similar way to a pregnancy test and the results are visible with 10 minutes. https://mologic.co.uk/wp-content/uploads/2018/05/PERiPLEXV2brochure_EN_FINAL.pdf. Positive results can give people a warning of an infection prompting them to contact their healthcare provider to initiate the specific antibiotic therapy. Earlier identification of infection enables pre-emptive use of available antibiotics, resulting in improved management of infection and prevention of infection-related damage to the peritoneal membrane.
Economic benefits. People spend less time in hospital awaiting diagnosis and are more able to positively engage with their family, friends and community. There is a huge reduction in overall NHS costs when people no longer need admittance to hospital and infection tests.
Addressing wider major global health concerns. People with infection are less exposed to unhelpful broad spectrum and stronger antibiotics this will reduce antimicrobial resistance, a major global health problem.
Improved collaborations with research and industry. The study was a highly successful partnership with the research team and industry partners Mologic. The system of testing has already been adopted for professional assistance in diagnosing bacterial vaginosis (BV) and new kits for researchers working on anything with a lateral flow visualisation system. https://mologic.co.uk/periplex/