COVID-19 diagnosis and reporting: why this is so important?
Like many other countries, Bangladesh is now started seeing more cases of COVID-19, it might sound like less number of positive cases and late diagnosis. We all need to keep in mind that, this has been the same in all other countries including the USA, where this slow rate of diagnosis has been pushed so much within a week that crossed the maximum number of diagnoses/day/week than any other country.
One obvious question is why to do this diagnosis even everybody is saying there is no specific treatment?
Whether a person is diagnosed or not, only one recommendation is ‘STAY HOME’. We might not be aware that early diagnosis of COVID-19 is critical, before spreading to the community and now this phase has been passed in Bangladesh.
So, why still diagnosis is needed?
Diagnosis is still critical in a global point of view. This means COVID-19 has a clear ‘incubation time’ within humans as a host. This means following incubation (14 days) there could be possibly two outcomes: some may get sick showing symptoms or some may remain healthy. Remember this 14 days incubation should start theoretically “when people locked in one place”, which is realistically impossible due to the fact that we would not listen that all at once.
Because of that, we lost track of where to set the clock. As a result, instead of 14 days, it might go longer. But still, under this situation, once we know the number of cases in the country, we would be able to see the ‘PEAK’ of cases in the next couple of weeks. If we all are very obedient, this will soon be turning around. This means the number of new cases will be lower.
“Flattened COVID-19 curve” what that tells?
This is good news for any country because under ‘HOME STAY’ condition there is less spread because the virus didn’t find a new host. So, locating this time point will tell us approximately when we probably can mentally be ready to open the country. Now, you can assume how critical this data is for a country because any mistake or lack of enough data will significantly affect the future.
Who should perform this duty?
This should be under the direct supervision of Bangladesh Primer Minister with a task force#1 built with Research scientists, few doctors, and supervisors of law-enforcement groups. Since there are a number of labs around the country getting samples and performing diagnosis tests, all results should be sent to the task force for the visualization of COVID-19 progression.
Only the Research Scientists will be in this task force for better coordination, accumulation of results and presentation. They need to perhaps discuss more often because of the nature of these tests. Accurate sampling, testing, and safety all need to be monitored by the group of scientists by teleworking.
Monitoring diagnostic test results and expectations:
1. COVID-19 diagnostic kits for 100 samples do not mean to successfully run 100 samples. Why?
In the Bangladesh context, this is super critical to understand that a test kit to be used for 100 samples should not put pressure on the lab workers to generate 100 results in your final report. Govt. People also need to understand that very well. You are running samples from patients that are with different amounts of viral load.
This means some samples though had symptoms that might be with a very low amount of material and could give confusing results. So lab workers need to repeat the test. They should not be driven by any force that we don’t have enough reagents and whatever data you got tell us it is positive or negative. If that happens would be a total disaster.
So, Kits made for 100 samples (#100 just give a number for comparison) would never generate 100 test results as final. It will be always less. This is the reality.
2. If the Diagnosis test becomes a nightmare?
Below seems to be a qPCR amplification chart. I believe it is from recent COVID-19 infected patient samples. It’s clear from the amplification curve but sounds like almost no amplification >35cycles. If that data was used to demonstrate a positive case, this is unreliable.
Who is in the frontline of performing this test, needs to be careful and make sure whatever kit you are using you are reproducing your positive curve provided by the kit. Make sure your negative samples not get amplified. It is expected to have data like below in each of your tests but important NOT to draw a conclusion. It is really important to be supervised by each of the diagnosis results by experts.
Unfortunately, this test takes lots of steps and needs to be done carefully. Ct cycle needs to be taken as a key to determining the positive or negative due to variation in the template concentration coming from all different patients. One critical thing when it goes to many hands and dealing with lots of samples, a little amount of DNA contamination from other samples could also lead that high Ct. values.
So, consensus should be to repeat that samples for the sake of patients.
BY Dr. Jubayer Rahman (PhD in Infectious Immunology), Maryland, USA