Testing in the time of Covid…

You might have heard about testing for Covid.

It is a thing.

It has experienced ups and downs and I’ll give you the background as well as my take on the position; beware – this isn’t what the government is advising, but who am I not to challenge them?

Testing started (locally at least) in Sheffield.

This was three or four weeks ago when the headlines described Sheffield as having the second highest number of Covid-positive people in the country, after London.

This was odd and, given Sheffield’s size, anomalous.

The explanation came when it was revealed that more tests were being done in Sheffield than other places; sure, Sheffield is the ‘big-city’ of South Yorkshire, but is isn’t that big and yes, it is more cosmopolitan than Rotherham or Doncaster, but it is hardly a melting-pot.

No, they were just doing lots of tests.

This wasn’t unreasonable and, in many ways, it was kind of helpful, in as much as it made people realise that many more people had Covid than either the government was admitting or was realised.

I am not sure the positive tests altered the outcomes, in other words, proportionately today, just as many people in Sheffield are infected with Covid and, just as many have died as other areas of the country.

This is the first question of any test, be it an x-ray, cholesterol level or brain-scan, if the results aren’t going to change the management (treatment) what is the point?

If you check a person’s cholesterol and you and they know their cholesterol is high from previous tests and they have refused to cut-down on cigarettes, alcohol or fatty food before, you have to wonder whether doing the same test again, with the inevitably abnormal results is worth the bother – ‘Your cholesterol is still high, too high,’ ‘I know doctor, I prefer to trust my body/God/luck/fate.’

Another consequence of the Sheffield mass testing was that South Yorkshire ran-out of tests for a couple of weeks; so, just as we were going into lockdown and the numbers of people likely to test positive were increasing, we ran-out and the tests were rationed.

I am told that everything will be fine by Monday; we will see.

The thing, beyond the cholesterol situation above, is the test’s sensitivity and specificity.

These are tricky terms;

Here is an attempt to explain:

Sensitivity – a test has to be adequately sensitive to detect most instances where something is normal or abnormal.

If, for example, you have Covid and the test is only 50 per cent sensitive, half the time when you take the test it will reveal you either have Covid (when you do) or you don’t have Covid (when you do) – it is this latter situation that is particularly pernicious.

If it tells you that you have Covid when you do, that is OK – you can do what you should already have been doing, hand washing, keeping your distance, I guess you might wear a face mask when you go outside to avoid infecting others, although you shouldn’t really be going-out, you should be indoors and preferably if you feel ill, in bed (or wrapped up in a blanket/duvet on the settee with book/Netflix);

If however you have Covid and the test wrongly tells you that you are fine (negative) – for the Covid test the sensitivity is between 50 and 75 per cent, which means (to reiterate) that between half of people who have Covid will be told they don’t, they might then think, ‘Oh, it’s just a cold, or maybe anxiety or allergies, I’ll carry-on regardless, cough and splutter their way around the supermarket, along the street, they might even tell friends and family, ‘I had a Covid scare, I tested negative though, so I (we, your granny, your asthmatic brother) am fine.’

I won’t go into the details of the test which is actually very specific – it detects the presence of particles of Covid DNA and as Covid-19 is quite different to other bugs going around, at least in the components of its DNA tested, the specificity should be OK; i.e. if the test tells you you have Covid, you likely do have Covid.

It gets more complicated when you take into account the skill/expertise of the person taking the swab, and perhaps whether the patient has just brushed their teeth, mouth-washed, had a cup of coffee; I don’t know for sure, there are likely other complexities.

And the test is only positive for the week you have the infection; afterwards the positives decline as it is cleared from your body, so, it is useless to tell you whether you had Covid a fortnight ago and have recovered; it is also no good at telling you whether you have contracted Covid the day after the swab was taken;

From Monday all care home residents will be swabbed before they leave hospital – this, whether or not they have symptoms.

The idea behind this is for information to be available to the care homes as to whether a resident returning from hospital should be treated as a patient i.e. someone who has Covid and is still infectious or as a resident, someone who has been unlucky to spend time in hospital during the time of Covid.

Again, sounds sensible.

Yet, the swabs are still liable to the errors and under-estimations I have already described.

If a swab is taken from a patient before they leave hospital, the results (in South Yorkshire anyway) can take up to 48 hours to return.

The guidance is for that patient to not delay in hospital but to return to their care home and wait as if they have Covid until a result is back (acknowledging that the result at worst can be 50-50).

This doesn’t consider the overwhelming (at times) complexity of hospital discharge processes which can take hours to achieve, during which, or perhaps in the ambulance or taxi home the person might contract Covid; they might even be tested negative for Covid but catch it from the care home when they get back.

It becomes crazy.

Some of this is taken into account by statisticians and epidemiologists; the irony however is, despite the ability of these bods to undertake complicated mathematical analyses and calculations, few, if any have worked in acute hospitals and an even smaller number have worked in care homes to be in a position to understand the little ins and outs of care, treatment, support, discharge and living that happens in these facilities.

I like my blogs to offer some sort of hope or solution; here is my stance – which again, is not the government’s (and, is it any surprise I don’t agree given that ideologically I have opposed pretty much everything they have done for the past decade, even before they got their hands on the sick and the vulnerable during the current crisis) (It’s a little like, ‘I wouldn’t trust you with my dog,’ versus, ‘I wouldn’t trust you with my dog when they are sick and I am not around) (sorry if that sounds harsh; these are harsh times).

My suggestion is that everyone in a care home is automatically regarded as being at the highest possible risk; the term we use in the UK is ‘shielding’ – people with organ transplants, who are receiving chemotherapy and other powerful drugs have been asked to self-isolate for three months.

Our mothers and fathers, brothers and sisters living in care homes don’t always tick the shielding box; they are however vulnerable, both because, in order to be resident in a care home in 21^st Century UK you have to be very frail, vulnerable and quite sick in the first place, you are also unavoidably exposed to close contact with lots of other people;

We have closed schools which has reduced transmission; we can’t close care homes.

I suggest therefore that everyone in a care home is treated as if they are at very high risk of contracting Covid and equally, the staff behave as if they are at high risk of infection and of infecting others.

This means maintaining distance, PPE, hand washing and so on.

I know this is very hard;

What do you do with those who have significant dementia and don’t understand the call to not move about? What do you do when a resident you have supported every day for the past four or five years is dying and you can’t hold their hand or allow them to spend time with family?

Yesterday I spoke with the family of a patient of mine who died of Covid.

Two days before he was well; they had been visiting him daily, passing their love and smiles through his bedroom window, they were preparing for his return home. He’d been in hospital and tested negative. This was him convalescing, getting to a position where he would be OK to be at home.

The next day he was dead.

I saw him before the end and he had all the symptoms and signs of Covid in older people, not necessarily the cough and the fever, but the pale, glazed, distant look that has become familiar to me; the drop in oxygen levels, the lack of response and the end.

Explaining to his family my diagnosis of Covid after he had tested negative for the disease was difficult.

He may have had then infection from the outset and he was one of the people who were false negative, he may have contracted the infection after that test, on the journey from hospital to the home, he might have caught it from another resident or member of staff; impossible to say.

Not only do the family have to contend with bereavement, they are also taken into a world of conjecture and uncertainty, all made worse by the traditional belief in medicine that is an exact science; it isn’t. There is much jiggery-pokery, analysis, consideration, weighing-up pros and cons, balancing the evidence.

It is a grey world and into that a test can help; it can also hinder.