Elon Musk says he tested both positive and negative twice for COVID-19 in one day

Elon Musk has claimed he took four coronavirus tests in a day, two coming back positive and two negative, and declared ‘something extremely bogus is going on.’ 

‘Was tested for covid four times today. Two tests came back negative, two came back positive. Same machine, same test, same nurse. Rapid antigen test from BD,’ the Tesla boss tweeted on Thursday.

The 49-year-old may have been referring to Becton Dickinson’s Veritor Plus system, a rapid antigen test which uses a nasal swab to produce a result in 15 minutes.

The FDA says that any negative result from the BD test should be verified by molecular testing – for example a polymerase chain reaction (PCR) test. 

Musk later revealed he was suffering ‘typical cold’ symptoms and warned of the contradictory results: ‘If it’s happening to me, it’s happening to others’. 

 

Elon Musk (pictured) has said he tested both positive and negative twice for COVID-19 as he declared ‘something extremely bogus’ is happening

The 15-minute, FDA-approved test works by taking a nasal swab from a patient

The 15-minute, FDA-approved test works by taking a nasal swab from a patient

Their documentation for the BD test warns that even a positive result ‘indicates the presence of viral antigens, but clinical correlation with patient history and other diagnostic information is necessary to determine infection status.’

Becton Dickinson’s Veritor Plus System

The 15-minute, FDA-approved test works by taking a nasal swab from a patient.

The cotton swab is then put into a tube and as it is withdrawn the sides of the tube are squeezed so that the liquid from the swab is caught inside.

A cap is placed on the tube and the sample is mixed thoroughly, either by swirling or flicking the tube. 

The contents of the tube are then dripped onto a stick-like device which has a small sample well at one end.

That stick is then left for 15 minutes before it is placed inside the BD Veritor Plus Analyzer machine.

The machine then produces the result on a display. 

FDA documentation for the BD test warns that even a positive result ‘indicates the presence of viral antigens, but clinical correlation with patient history and other diagnostic information is necessary to determine infection status.’

As regards a negative result, it says: ‘Negative results are presumptive. Negative test results do not preclude infection and should not be used as the sole basis for treatment … It is recommended that these results be confirmed by a molecular testing method.’  

In October, Nevada health officials ordered nursing homes to stop using two rapid antigen tests after nearly two-thirds of the tests were false-positive, or people were mistakenly told they were infected with the virus.

The tests were the Quidel Sofia II and the Becton Dickinson (BD) Veritor Plus, the latter being the company behind the tests Musk said he used. 

Source: FDA 

As regards a negative result, it says: ‘Negative results are presumptive. Negative test results do not preclude infection and should not be used as the sole basis for treatment … It is recommended that these results be confirmed by a molecular testing method.’ 

Last week, the FDA said it was alerting clinical laboratory staff and healthcare providers that false positive results can occur with COVID-19 antigen tests. 

BD, which is one of the major suppliers of COVID-19 antigen tests, said in September it was investigating reports from US nursing homes that its rapid coronavirus testing equipment was producing false-positive results.

In October, Nevada health officials ordered nursing homes to stop using two rapid antigen tests after nearly two-thirds of the tests were false-positive, or people were mistakenly told they were infected with the virus.

The tests were the Quidel Sofia II and the BD Veritor Plus, the latter being the company behind the tests Musk said he used.

A similar test from AbC-19 was also found to only be 81.7 per cent accurate at diagnosing a positive result, according to a study this month in the British Medical Journal. 

Researchers yesterday accused the British government of ‘jumping the gun’ by purchasing a million of the AbC-19 tests in an undisclosed deal before thorough analysis was published. 

Several Twitter followers joined in Musk’s discussion questioning the inaccuracies and asking about the eccentric entrepreneur’s symptoms. 

‘Could this be why we’ve been seeing such a major spike?’ one person wrote. 

‘If it’s happening to me, it’s happening to others. I’m getting PCR tests from separate labs. Results will take about 24 hours,’ Musk wrote. 

‘Symptoms of a typical cold. Nothing unusual so far,’ he replied to another about his condition. 

Musk then seemed to take a swipe at companies developing the tests, responding ‘exactly’ to someone who wrote that the ‘revenues from tests are likely not bogus & very consistent.’ 

In a follow-up tweet Musk then added: ‘The carousel turns ever faster.’ 

Musk has repeatedly downplayed the extent of the virus which has so far killed more than 242,000 Americans. 

Back in March, he fired off a tweet dismissing rising fears over the coronavirus outbreak as ‘dumb’ as cases continued to mount across the US. 

Musk, 49, then responded to a series of comments from followers where he revealed he was suffering 'typical cold' symptoms and warned 'if it's happening to me, it's happening to others'

Musk, 49, then responded to a series of comments from followers where he revealed he was suffering ‘typical cold’ symptoms and warned ‘if it’s happening to me, it’s happening to others’

He then incorrectly told his 39 million followers that children were ‘essentially immune’ to the virus and blasted the nationwide lockdowns as ‘de facto house arrest.’ 

Musk then appeared to have a change of heart, however, when he delivered over 1,000 ventilators to a California hospital and vowed to reopen Tesla’s New York factory as soon as possible to help make and distribute ventilators to the embattled state. 

But in September, Musk then doubled down on his claims that COVID-19 doesn’t pose a risk to children and said he wouldn’t take a vaccine when it became available. 

‘I’m not at risk for Covid, nor are my kids,’ he said in an interview on New York Times podcast ‘Sway.’  

A medical staff takes a nose swab sample for a COVID-19 rapid test. Experts have raised concerns about rapid antigen tests which are much cheaper and faster than nucleic acid tests but are considered to be far less accurate

A medical staff takes a nose swab sample for a COVID-19 rapid test. Experts have raised concerns about rapid antigen tests which are much cheaper and faster than nucleic acid tests but are considered to be far less accurate

His most recent comments come as experts have repeatedly raised concerns about the accuracy of rapid tests. 

Rapid antigen tests are much cheaper and faster than the alternative nucleic acid tests and promise results in just 15 minutes.

However the nucleic acid tests, also known as RT-PCR tests, are considered the gold standard of COVID-19 testing.

They diagnose patients by detecting RNA, or viral genetic material.

Antigen tests look for viral proteins and are considered to be far less accurate. 

MailOnline has asked BD for comment. 

TRUE PREDICTIVE VALUE: HOW EVEN A GOOD TEST CAN LEAD TO WRONG RESULTS 50% OF THE TIME

The US’s Centers for Disease Control & Prevention warned in May that coronavirus antibody tests may be wrong 50 per cent of the time even if they are high quality.

It warned that the antibody testing is not accurate enough for it to be used for any policy-making decisions, as even with 95 per cent test specificity, ‘less than half of those testing positive will truly have antibodies’.

This is why:

Antibody tests with what could be considered a high level of accuracy can still produce large margins of error if only a small proportion of a population has been infected. 

A 95 per cent specific test, for example, will always produce five false positive results from a group of 100 people.

Even if it is sensitive enough to detect all the people who have genuinely had the disease, it will still return five false positives, and the effect this has on the results of a survey can be large if the number of true positives is low.

If the prevalence of antibodies is low – for example, only five per cent of people in the group have had the illness – the results could end up half wrong. The 95 per cent test, in that situation, would be expected to return 10 positives – five of them right, five of them wrong.

This means the functional accuracy of the test, known as its true predictive value, is only around 50 per cent.

The effect of these false positives is magnified if the prevalence of the virus in the population is low, and less noticeable if the prevalence is high.

For example, if 30 per cent of the population have been infected, those five false positive results would be counter-balanced by 30 true positives, making the test more like 85 per cent accurate.

A more specific test can reduce this effect; by comparison a 99.9 per cent specific test would return one wrong result per thousand – 100 per million. 

Read more at DailyMail.co.uk