Setting the Standard: Digital PCR's Role in Accurate Infectious Disease Testing
Diagnosis of infectious diseases often requires accurate testing to detect the presence of the causative pathogen. However, without standardisation to underpin test performance, we cannot know for sure if a test result is accurate. This undermines the confidence and impact of the test in question.
As the UK's Designated Institute for Chemical and Biological Metrology, at the National Measurement Laboratory at LGC, we have a rich history of providing high accuracy reference methods and materials to standardise measurements and ensure accuracy of infectious disease diagnostics.
Speaking to Madeleine Johnson at #genomeweb, Jim Huggett, Director of Biological Metrology at the National Measurement Laboratory (NML) at LGC, discussed the team’s research using digital PCR as a reference method to standardise test results between laboratories. Jim explained that standardisation is an especially important safeguard for diagnostic tests that are used without other clinical criteria such as when screening of asymptomatic populations or those that require immediate clinical intervention where there may not be time for corroboration to confirm finding.
Harnessing the precision of digital PCR, a global team of measurement experts led by the NML at LGC have developed a reference measurement procedure (RMP) that standardises nucleic acid amplification test (NAAT) results. This breakthrough research, published in Clinical Chemistry journal, has the potential to support quality assurance, even in prior to the development of international reference materials which are currently used to ensure traceability.
As highlighted in an associated editorial in Clinical Chemistry, during COVID-19, NAAT's were quickly developed and deployed by diagnostic test laboratories to counter the spread of disease. However, the sensitivity of such tests was initially unknown and subsequently discovered to vary widely. In the worst-case scenario, low sensitivity tests can lead to false-negative results which, if trusted, can directly lead to wider spread of the disease they are intended to control.
Physical reference materials allow laboratories to compare NAAT results as part of their external quality assurance (EQA) processes. However, these materials take time to produce and cannot be developed and distributed as quickly as the diagnostic tests they are intended to support. This work explores the use of RMPs as a complementary route to support standardisation alongside physical standard materials. Such methods can be developed and applied at a similar pace to the diagnostic tests that are often seen as vital to infectious disease management.
This research builds upon the NML at LGC's efforts working with the wider metrology community to raise awareness of the importance of accurate and rapid diagnostics to support pandemic preparedness- as it is not a case of if, but rather when, there is a future infectious disease outbreak.
Access the publication here- https://pubmed.ncbi.nlm.nih.gov/39724302/
Read the editorial here- https://academic.oup.com/clinchem/advance-article-abstract/doi/10.1093/clinchem/hvae225/7965244?redirectedFrom=fulltext
Read the Genomeweb article here- https://www.genomeweb.com/molecular-diagnostics/digital-pcr-reference-method-improves-inter-lab-qpcr-variability-study-finds