Why are so many tests coming out as negative?

[bear66]

We're only testing people in hospital with Covid-19 symptoms; there have been approximately 60000 tests in the past week, but less than 20000 positives. Presumably these are quite sick people presenting themselves or 111 would tell them to self isolate at home. Seems a lot of negatives with severe symptoms similar to Covid-19.

 

[HolgateCorner]

It may be because cold and flu symptoms are similar or it may be people who just make symptoms or reasons up to get a test to reassure themselves.

The mind is a funny thing, it can invent symptoms for itself.

 

[kuepper]

from gov.uk "As of 9am on 29 March 2020, a total of 127,737 people have been tested, of which 108,215 were confirmed negative and 19,522 were confirmed positive" - total figures since it began not just last week. Better to test and check than not test I guess. BTW my GP has just tweeted about this survey

https://covid19-survey.org/

 

[bear66]

It's a lot of tests that have been 'wasted' instead of doing more important NHS staff tests. You're probably right though. Fever / test.

 

[bear66]

from gov.uk "As of 9am on 29 March 2020, a total of 127,737 people have been tested, of which 108,215 were confirmed negative and 19,522 were confirmed positive" - total figures since it began not just last week. Better to test and check than not test I guess

In the early days they were testing people who had been to an infected country even when no symptoms.

 

[Billy Horner]

Looking at the NHS hospital statistics for 2018-19, there were almost 1m hospital admissions for respiratory illness (influenza and pneumonia being the main sub-category with 300k). Presuming that’s a typical year, I suppose that’s going to lead to a lot of negative tests in the current climate.

 

[Redpete]

One of the problems is the accuracy of the tests, its expected only a 70% accuracy rate at the moment
Spain returned 50k Chinese kits that were thought to be only 30% accurate.
If this is correct it makes a mockery for the call of more testing there is little point if you dont have confidence in the results.

 

[bear66]

One of the problems is the accuracy of the tests, its expected only a 70% accuracy rate at the moment
Spain returned 50k Chinese kits that were thought to be only 30% accurate.
If this is correct it makes a mockery for the call of more testing there is little point if you dont have confidence in the results.

A Northern Ireland / Bosch consortium have developed an automated testing machine with 2.5 hours from swab to result and 95% accuracy.

 

[MrIsaac]

An unreliable test is worse than no test at all. The words of Chris Whitty who used this line as one of the reasons the UK is still waiting for testing kits. They will only use test kits that have a very high proven reliability.

 

[Alvez_48]

The current test is very specifically trying to find the virus itself (very hard) and only if they are present in the exact moment will they show a positive result.

The new tests searching for anti bodies will give a far better picture. Pray for all of us that these show that many people have the anti bodies present otherwise there really is no easy way out in terms of assessing the situation and acting accordingly.