DIAGNOS TICS
Rapid detection of infection
Point-of-care testing, in the form of lateral flow testing for SARS-CoV-2 antigen, has become familiar to many during the ongoing COVID-19 pandemic. Here, Carolyne Horner discusses the diversity of point-of-care tests (POCTs) available for the rapid detection of infection and the key issues relevant to their uptake by UK healthcare.
Since the emergence of the SARS-CoV-2 virus and ongoing COVID-19 pandemic, awareness of infectious diseases and the need for rapid diagnostic tests has never been higher. While a defined timeframe for a ‘rapid’ diagnostic test is lacking;1
most would
agree that provision of results to the end user within two hours would qualify.2 Broadly speaking, a diagnostic point-
of-care test (POCT) is “testing that is performed near or at the site of the patient, with the result leading to a possible change in the care of the patient.”3
However,
definitions vary and there is an ever-growing list of alternative names for point-of- care (including, rapid diagnostics, near patient, satellite, decentralised, remote or patient centred testing). Point-of-care and near-patient testing tend to be used interchangeably, whereas other terms are more bespoke according to requirements. Given the level of variation associated with POC testing, a grading system based on the location and person completing the test has been suggested (Table 1).1 In addition, the World Health
Organization (WHO) proposed that an ideal POCT, especially one suitable for use in low resource settings, should achieve the assured criteria and be affordable, sensitive, specific, user-friendly, rapid and robust, equipment-free and deliverable to end users.4
Diversity among POCT The true benefits of a POCT are realised when the test is completed outside a standardised laboratory environment by someone who is not laboratory trained. By their nature, POCTs are simple to operate and require limited expertise to complete, they have a low number of processing steps, equating to minimal hands-on time, and
Fig. 1 A molecular panel syndrome-based point-of-care test (BioFire FilmArray Torch System, showing the panel kit, pouch loading station and analyser).
have easy-to-interpret results. There are many POCTs available for the
detection of infection, ranging from simple dipstick-type tests to molecular-based syndromic testing (Table 2 and Figures 1-4). Even for detection of the same infection, vast differences exist between POCTs, some of which are listed below: l Is it a standalone test, such as a dipstick or lateral flow?
l Is it simple or complex in terms of analyser/ additional equipment requirements?
l What is the target analyte: pathogen- specific or surrogate marker of infection, such as a change in immune response?
l What are the range of analytes detected: single or multiple analyte detection or molecular syndromic testing?
l What is the technology of detection: antigen, immunoassay, or molecular? l How easy is sample collection:
32 l
WWW.CLINICALSERVICESJOURNAL.COM finger prick blood, nasal swab?
l What is the time to result: <5 minutes to <2 hours?
Understanding the diversity among the POCTs available for detection of infection is important when interpreting the results of systematic reviews, the conclusions of which frequently acknowledge considerable heterogeneity in studies eligible for inclusion,5
making recommendations for
clinical practice difficult, due to the level and quality of evidence available. Variations among POCTs also become important when anticipating and addressing barriers to implementation.1
For instance, POCTs
suitable for a GP consultation are likely to be different to those suitable in an emergency department, in terms of the time-to-result, range of pathogens detected, cost of the analyser/test.
DECEMBER 2021
©bioMérieux
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56
