The evidence base consisted of one good quality systematic review (23 observational studies of poor quality) and a further four non-UK observational studies published since the NICE diagnostic guidance in 2017.
Due to observational study designs, the overall evidence is not robust and data on morbidity, mortality and quality of life outcomes is lacking Integrated GPPs demonstrate consistently faster turnaround time than conventional tests, which may be associated with improved antibiotic use and reduced requirement for additional diagnostic tests. Testing using GPPs did not affect length of hospital stay compared with conventional methods.
There is substantial uncertainty around the probability of cost effectiveness due to lack of clarity on the diagnostic accuracy of GPPs and the absence of patient outcome data.
- In hospitalised adults, children and people who are immunocompromised, the probability of cost effectiveness of GPPs (Luminex xTAG® and Biofire FilmArray™ is around 54-58% compared with conventional testing.
- In the recently returned from travel population and for patients in community settings the probability of cost effectiveness varied widely between the Luminex xTAG® GPP (99-100% probability) and the Biofire FilmArray™GPP (6% probability) compared with conventional testing. PCR tests could be useful as preliminary screening tests, particularly in the case of potential outbreaks of harmful infectious pathogens, such as Shiga-toxin producing E.coli. Positive PCR results should be confirmed by culture.
More robust evidence on clinical effectiveness may become available following completion of ongoing randomised controlled trials (RCTs). One UK study is due to be completed in September 2020 (GastroPOC). A US study is due to be completed in November 2019 (NCT03809117).
What were we asked to look at?
We were asked to examine the evidence on testing with multiplex polymerase chain reaction (PCR) gastrointestinal pathogen panels (GPPs) compared with conventional testing methods in people with suspected gastroenteritis.
Why is this important?
Conventional testing comprises multiple tests, such as immunoassay and stool culture, which can take several days to return results. Multiplex PCR GPP tests return results within hours. A faster diagnosis has implications for improved cost effectiveness and patient management outcomes, such as reduction in empirical antibiotic prescribing, length of hospital stay and use of isolation bays. Rapid detection of infectious pathogens can also limit and prevent outbreaks.
The Scottish Microbiology and Virology Network (SMVN)