A joint statement from the microbiologist and medical laboratory scientist collective – APHG laboratory network

We reject the serious allegations made by Dr Anne Wyllie against the SARS-CoV-2 saliva testing being performed through the Asia Pacific Healthcare Group (APHG) network of diagnostic laboratories. These laboratories include Wellington SCL, Dunedin SCL, Canterbury SCL and Labtests Auckland, which have a proven track record for providing quality diagnostic services to New Zealanders, and include a team of Clinical Microbiologists and Medical Laboratory Scientists who assume clinical and scientific responsibility for the diagnostic microbiology services we provide.

Dr Wyllie made a number of inaccurate statements on the RNZ Nine to Noon programme on 7th September that have served to cast doubt on the performance of our assays and the integrity of our work as registered healthcare professionals. We would like to correct these statements and provide absolute reassurance to New Zealanders that we take very seriously our responsibility to provide high quality diagnostic services which are reliable and trustworthy.

Dr Wyllie stated that we are simply applying an assay to saliva samples and “hoping that it works” with no clinical validation (using real clinical samples) to assess performance. To allege we are not following a rigorous process for the validation of our diagnostic tests, without any evidence or knowledge about our process, is unjustified and directly attacks our professional integrity and standards. Dr Wyllie is not experienced in the diagnostic clinical laboratory space, has not seen our validation data, nor has she sought to contact us to discuss it, but instead has decided to make defamatory statements in the media.

As Clinical Microbiologists (pathologists) and medical laboratory scientists we are well versed in diagnostic test validation, not just for COVID-19, but for all the medical testing we provide. We take full professional responsibility for the diagnostic work that our laboratories do. Our individual professional practice and wider laboratory standards are regulated by the New Zealand Medical Council, the Royal College of Pathologists of Australasia, the New Zealand Institute of Medical Laboratory Science, the New Zealand Medical Sciences Council and International Accreditation New Zealand (IANZ) respectively. Strict adherence and compliance with good laboratory practice and quality standards is at the core of what we do, every single day.

For the record, we have completed both a technical (analytical) validation using spiked saliva specimens, and clinical (‘diagnostic’) validation, using saliva samples kindly provided by volunteers in Managed Isolation and Quarantine facilities within New Zealand, for all of the assays we are utilising for SARS-CoV-2 saliva testing in the APHG laboratory network. It should be noted that both aspects of validation offer important and valuable information to understanding test performance. In conjunction with the ESR we have also demonstrated our test performance is equivalent or superior to both the SalivaDirect and covidSHIELD extraction-free methods Dr Wyllie is attempting to promote as ‘gold standard’.

Whilst we acknowledge Dr Wyllie’s work for saliva diagnostics, we believe it is disingenuous of her to state that her or like methods are the only valid procedures that should be followed. A wide range of assays are in use for nasopharyngeal PCR, for example, and this will (is) also be the case for saliva testing that utilises the same PCR technology applied to a different sample type. Similar to nasopharyngeal samples there is no one ‘best test’ to successfully detect SARS-CoV-2 in saliva but rather a range of suitable options; alternative assays can be perfectly well optimised for use with saliva, as Dr Wyllie should know.

Dr Wyllie states that an extraction-free method for saliva testing offers a faster and less complex way of testing. We disagree with the significance placed upon this because this particular part of the testing process forms only a small part of the overall time it takes to return a result from the time the sample is collected. Different platforms for SARS-CoV-2 already have variable testing times (from 1 to 6 hours) and other factors, which include transport, registration and resulting procedures (which all take time to do safely) contribute significantly to the total time for the test. Any time saving by removing extraction is relatively small considering the overall process. At this stage we have taken the decision that optimising test sensitivity (by including an extraction step in our PCR methodologies) is important to support Aotearoa New Zealand’s successful elimination strategy. This is very different from Dr Wyllie’s situation in the United States, where COVID-19 has been allowed to circulate widely and where small differences in test sensitivity are unlikely to have a major clinical or public health impact.

Dr Wyllie has stated that laboratories in Aotearoa New Zealand have not been collaborative. As a research scientist based in the United States it is puzzling that she should make a claim against those working at the coal face in New Zealand. In fact, the New Zealand Microbiology Network, made up of clinical microbiologists from all diagnostic microbiology laboratories across New Zealand and ESR, has been meeting every 1-2 weeks, to openly discuss testing strategies, performance and other COVID related clinical and laboratory matters. In addition, representatives from the New Zealand microbiologists community have attended the weekly Australian Public Health Laboratory Network meetings and been liaising with colleagues from Public Health England, other European agencies, and university colleagues, as well as Dr Wyllie herself.

Our laboratory response in Aotearoa New Zealand has been dedicated, agile and world class. The APHG laboratories were among the first to develop and stand-up nasopharyngeal PCR testing at the beginning of the pandemic and have since performed over a third of the three million tests performed in New Zealand to date. The response from APHG and its clinical microbiologists and medical laboratory scientists has been a crucial part of the collective nationwide response to COVID-19 and the success to date of our national elimination strategy.

To conclude, we are fully satisfied that our SARS-CoV-2 saliva testing is robust and reliable. It is clinically (diagnostically) validated and is IANZ accredited. We have collaborated extensively to get here, are extremely proud of our team, and are dedicated to upholding the quality of our service for the benefit of New Zealanders.

Signed and endorsed by:

Dr Michelle Balm, MBChB, DTM&H, FRACP, FRCPA, Consultant Clinical Microbiologist and Infectious Diseases Physician.
Dr Vivian Black, MBBCh,  MSc, FCPath, Consultant Clinical Microbiologist.
Dr Tim Blackmore, Consultant Clinical Microbiologist and Infectious Diseases Physician.
Dr Matthew Blakiston, MBCHB, MTID, MSc (MedMicro), FRCPA. Consultant Clinical Microbiologist.
Dr Max Bloomfield, MBChB, MPhil, MSc, FRACP, FRCPA. Consultant Clinical Microbiologist and Infectious Diseases Physician.
Dr Juliet Elvy, BMedSci, BMBS, MRCP, FRCPath, FRCPA. Consultant Clinical Microbiologist.
Dr Jenny Grant, BMLSc, PGDipMLS, PhD. Medical Laboratory Scientist.
Dr Aaron Keene, BMLS, MBChB, FRCPA Consultant Microbiologist.
Ms Gayleen Parslow, Certificate of Proficiency in Medical Laboratory Technology NZIMLS, Medical Laboratory Scientist.
Ms Susan Smith, BMLSc, Medical Laboratory Scientist.
Mr Chor Ee Tan, B.Tech (Hons), Medical Laboratory Scientist.
Associate Professor James Ussher, MBChB, PhD, FRCPA, Consultant Clinical Microbiologist.
Mr Koen van der Werff, BMLSc, Medical Laboratory Scientist.
Ms Catherine Gordon, BMLSc. Medical Laboratory Scientist
Mr Tony Barnett, MNZIMLS, Medical Laboratory Scientist