As the US continues to see a rise in the numbers of COVID-19 cases, the country’s health officials are considering a new testing strategy to determine just how many people have been exposed to the virus. Called pool testing, the proposed strategy involves combining samples from multiple people and testing as a group.
Speaking to media persons, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, admitted that the country’s current approach of only testing symptomatic COVID-19 patients and tracing their contacts isn’t working. This is because asymptomatic people are spreading the virus unknowingly.
To improve the COVID-19 surveillance, Dr. Fauci said officials are talking about implementing pool testing. Experts believe that pooling would boost the country’s testing capacity from half a million tests a day now to potentially 5 million tests per day. Prior to the coronavirus pandemic, pool testing was only used in blood banking. How it will be used for SARS-CoV-2 testing? Will it help contain outbreaks of COVID-19? Keep reading to know all about the proposed testing strategy.
How pool testing works
Pool testing also uses the same polymerase chain reaction (PCR) technology like the current diagnostic tests, but it is the method by which people are tested which makes this approach unique.
In this method, samples from multiple people are combined and tested at one time. If the result is negative, it means the entire group is negative for the coronavirus. However, if a pool gets a positive result, it will be moved to the second phase of testing that involves breaking down the pool into smaller samples to identify the infected person or people.
The number of samples used for pool testing may depend on the type of machine being used for the test. While some say that up to 10 samples could be pooled in, others recommend up to 50. A preprint study from Israel suggests that the virus can be detected in a pool with as many as 64 samples.
Advantages of pool testing
Some experts opined that implementation of pool testing can increase the number of people tested tenfold. It is also more cost-effective and can reduce the burden on laboratories. Pool testing will help identify asymptomatic COVID-19 patients and weed out those who are not infected. This method is less time-consuming and so it will speed up the testing process.
Drawbacks of pool testing
The main drawback of this method is that it’s not a foolproof approach. If the number of infected people is too high in the initial sample, it may be difficult to identify them in the group.
Again if the pool is too large, the samples can be less viable. There are chances that some positive cases might show up as negative after diluting with large numbers. Moreover, pool testing may not be suitable everywhere as there are variations in the prevalence of the disease.
According to some experts, pool testing is best in places with low rates of COVID-19, where there are high chances that the large majority of tests would be negative. Another disadvantage of pool testing is that when the test result turns out positive, all the samples must be retested individually. This long gap in confirming the test could cause anxiety among people who are waiting for their individual results.
Published : July 1, 2020 3:41 pm | Updated:July 2, 2020 6:36 am
