Yesterday wallpaper2 asked for a comparison of the available antigen tests to which I replied briefly. I now have time to further compare the 5 antigen tests awaiting HC Approval which I detail below. Obviously I am slightly biased as I have always believed, and continue to believe, that the SONA test is the best antigen test currently out there and that antigen testing will be the basis of getting the world back to normal with Screening of the Asymptomatic population including schools, universities, workplaces, public transport and sports stadia as well as general Screening Programmes ( several are already planned with the UK for example talking about spending 100 billion on their testing programme and planning for widespread testing for at least 2 years) and so my assessment should be read with this in mind but this analysis is based on readily available FACTS and I am open to any challenge on the veracity of the information that I provide:
1. BIOCREDIT COVID-19 Ag - RAPIGEN Inc. South Korea
a LFA, machine-free test that is quick and well priced. Used extensively in Far-east and in South America primarily due to it´s low-cost. They claim Sensitivity of 92% and Specificity of 98% but several bodies dispute these accuracies suggesting results are very much lower. This for example is from a recent study carried out in South America:
"We compared the performance of four rapid antigen detection tests for SARS-CoV-2 in respiratory samples. Immunochromatographic SARS25 CoV-2 assays from RapiGEN, Liming bio, Savant, and Bioeasy.
The overall sensitivity values of RapiGEN, Liming bio, and Bioeasy tests were 62.0% (CI95% 51.0–71.9), 16.7% (CI95% 10.0–26.5), and 85.0% (CI95% 75.6–91.2), respectively, with specificities of 100%.
In addition, we correlated the viral loads of samples with true positive and false negative results. As shown in Figure 1, mean Ct values of false negative samples were significantly higher than in true positives samples in all three tests. RapiGen and Bioeasy mainly missed to detect samples with low viral load (Ct values >25); this threshold was less clear for the Savant assay. Accordingly, sensitivity values of RapiGen and Bioeasy differed significantly among subgroups with high viral loads and low viral loads (Ct >25) (Figure 2). Indeed, the two assays identified 84.9% and 100% of specimens with high viral load, but only 15.4% and 53.8% of those with low viral load, respectively.
The RapiGen test also showed an acceptable sensitivity (84.9%) with high viral load samples, but was much less sensitive (15.4%) when the viral burden was low
However, it is important to note that the CE licencing process is based on self reporting of manufacturers, does not grant high performance, and can be misused."
The Rapigen test failed miserably ( you can also see a published article on this test below in the SD BIOSENSOR review) and this is not the only example of such findings. The last statement explains, for those who are wondering, why they achieved CE licensing and why they have then on that basis applied for HC and FDA Approval. If these authorities investigate their claims ( as I am certain that they will as they have no 3rd party Validation) they will almost certainly not receive Approval from neither HC nor FDA.
2. PANBIO ABBOTT.
this test as we know is produced by a Major USA Company, is easy to use, cheap and quick. It has very good published Sensitivity and Selectivity figures but these were produced only on proven Symptomatic patients well established in their infectious phase. In addition while their accuracy on high-viral loads was excellent it was much less so on patients with low-viral loads . They also have no tests on Asymptomatic patients( not really surprising that they didn´t test on this group in view of the above). They also have no 3 rd party Validation and can offer no independent accuracy figures. This is particularly relevant because the accuracy of their test has been questioned on several occasions attracting widespread media coverage which you can find online.
One such case was in Vermont and here are a few extracts:
In mid-May, the Food and Drug Administration issued a rare public warning about an Abbott Laboratories COVID-19 test that for weeks had received high praise from the White House because of its speed: Test results could be wrong. The agency at that point had received 15 “adverse event reports” about Abbott’s ID NOW rapid COVID test suggesting that infected patients were wrongly told they did not have the coronavirus, which had led to the deaths of tens of thousands of Americans. The warning followed multiple academic studies showing higher “false negative” rates from the Abbott device, including one from New York University researchers who found it missed close to half of the positive samples detected by a rival company’s test. The FDA has now received a total of 106 reports of adverse events for the Abbott test, a staggering increase.The agency has not received a single adverse event report for any other point-of-care tests meant to diagnose COVID-19, an agency spokesperson said. “Everybody was raving about it,” a former administration official said, speaking on the condition of anonymity to discuss internal deliberations. “It’s an amazing test, but it has limitations which are now being better understood.” Abbott will have been working on their test to try to improve it but their failure to carry out 3rd Party Validation leaves significant doubt. They have also changed the name of their test although I can find no evidence to suggest that it is not exactly the same test, which also casts doubt on their motives. You may remember how their CEO and their Chief Scientific Officer avoided answering any awkward questions on the Trial patient population, the absence of Asymptomatics etc. and yet ,at the same time, seemed to quite dishonestly imply that their test could help in Screening. They will, obviously, get Approval and will be very successful because it seems to be a good test but it still leaves a lot of unanswered questions and clearly at this stage cannot be used in a general Screening Programme.
3. QUIDEL SOFIA 2.
This test requires a machine which is expensive and only runs one test at a time. It is licensed only for lab use and on Symptomatic patients.It will be Appproved (but perhaps not fast-tracked because of the machine and lab use), is accurate and has it´s place but will not be a true competitor to the Abbott or Sona tests.
4. SD BIOSENSOR South Korea.
Again a LFA machine-free test widely used in Far-east and 3rd world. It is cheap and easy to use. Only for use in Symptomatic patients in the acute phase of infection. Testing was done by a hospital in China and they claimed Sensitivity of 89% and Selectivity 99% but these claims have been challenged by many authorities. 2 major studies in India and Malaysia, where the test is
used widely, claimed the Sensitivity ranged only between 50.6% and 84%.
Here also are excerts from a study published last month :
"The present study was aimed at evaluating the performance of two COVID-19 rapid antigen detection tests, which are BIOCREDIT COVID-19 Ag (RapiGEN Inc., Korea) and Standard Q COVID-19 Ag (SD Biosensor, Korea), in comparison with RT-PCR. BIOCREDIT COVID-19 Ag and SD Biosensor RAD kits recorded total sensitivities of 52.5% and 68.7% and specificities of 46% and 96%, respectively. In high viral load samples, BIOCREDIT COVID-19 Ag and SD Biosensor RAD kits recorded higher sensitivities of 60% and 77%, compared to 45% and 60% in normal viral load samples, respectively."
These results are really rather poor and their CE certification is again based on information provided by the manufacturer and not backed up by independent Validation.
It is worth remembering that Spain in the earlier phase of the Pandemic tried to use tests such as this one and the SD BIOSENSOR, ie produced in Far-east and with CE certification and had to return them all (700k) as both batches received did not work accurately. Again, as for the RAPIGEN test above, if HC and FDA investigate the reported accuracies they will almost certainly not receive Approval.
4. SONA :
A. Sensitivity of 96.7% and Selectivity 96.6% in lab testing.
B. 3rd Party Validation of above with low LOD.
C. Sensitivity of 84.6% and Selectivity 90% in in-field testing which is more than acceptable for HC and FDA Approval.
D. Sensitivity of 100% and Selectivity 100% on Asymptomatic patients in in-field testing.
E. It is rather unusual and unexpected to have better accuracy in Asymptomatic patients than in Symptomatic patients and this has led to much discussion. What may be very relevant is that the Symptomatic patients were hospitalised and for an indeterminate period. A widely held theory, with logic behind it, is that many of the hospitalised patients may have passed the acute infectious stage and were therefore non-contagious but had traces of viral RNA debris left behind from the infectious stage that was insufficient to be picked up by the Antigen test but was picked up in the later (very intensively amplified ) cycles of the ( over-sensitive ?)PCR machines. The acceptance of positivety based upon encountering RNA using in excess of 33 cycles of a PCR machine has been called into question. Several experts, including Michael Mina, have gone on record stating that they do not consider such patients either positive or contagious. This argument, becoming more widely accepted by the day, could well explain why the SONA test picked up all of the Asymptomatic cases but missed so-called postives who were no longer contagious. This, if shown to be correct, would make the SONA the perfect screening tool.
F. SONA test is cheap(ish), machine-free, lab-free, quick and easily used.
G. SONA have close connection to SAUDIVAX and Saudi Arabia which is very interesting.
H. SAUDIVAX are processing Approval by Saudi Authorities and have said that they consider it suitable for the Saudi Screening Programme and I believe that other countries will follow.
I. SONA has the unique testing and tracing system developed by BOND which is the type of system that the regulatory bodies are demanding be in place before they approve home testing in order that results are automatically forwarded to the health authorities for both individual health and epidemiological puposes.
F. SONA are a small Company but have the partnership and support of Cytiva, a major player in the diagnostic testing field and a subsiduary of Danaher( market cap 150 billion) so will not lack expert help and advice in marketing and manufacturing strategy.
G. SONA´S main challengers are already billion dollar companies whereas SONA has a much smaller market cap and a small share float which should mean that success will increase the SP with much greater effect.
I obviously personally think that SONA has the best test out there at present, based on their propietary and patented GNRs which I believe is the reason for the excellent performance of the test. I am sure that Approvals and mass production will be achieved and that the share price will reflect that success in the near future. Do your own research and DD and come to your own conclusions and GLTA.
PS Saw a post this morning about the BD test. Exactly the same limitations as QUIDEL and detailed above.