COVID-19 is one of the most dreaded respiratory health conditions. It can make individuals suffer from severe illnesses, especially if they have pre-existing conditions. COVID-19 can be more dangerous for someone who has been suffering from diabetes, high blood pressure or obesity. Testing is one of the most effective measures to minimise the spread of this respiratory infection.
Individuals can carry out a covid self test or visit a healthcare facility with well-equipped laboratories to get tested. These tests are responsible for identifying the presence of SARS-CoV-2, a virus that causes COVID-19. There are two types of tests for coronavirus, both of which have been instrumental in ensuring that infected persons do not infect their close contacts.
But are these tests accurate? In this article, we discuss both tests in depth to help you understand the accuracy of each and make informed decisions about your personal health and public safety.
What Are the Types of COVID-19 Tests?
As mentioned above, these tests check whether the individual has a current SARS-CoV-2 virus infection. The latest statistics in England, done on the 16th of November in 2023, showed 4549 positive cases in 1 week. That included the individuals testing positive for the first time and those who were re-infected.
Covid 19 tests require specimens from your mouth or nose. They include:
- The antigen tests
- The polymerase chain reaction (PCR) tests
Polymerase Chain Reaction (PCR) tests
Polymerase Chain Reaction (PCR) tests among the types of the nucleic acid amplification test (NAAT). PCR tests have a higher likelihood of detecting the virus than antigen tests. In fact, they are also known as the gold standard when it comes to COVID-19 diagnosis.
They detect the genetic material of the virus, which provides a highly accurate and reliable method for identifying infections. The sensitivity and specificity of PCR tests contribute to their effectiveness, allowing for the accurate identification of both infected and non-infected individuals.
PCR tests have been instrumental in various stages of the pandemic. From early detection in symptomatic individuals to widespread community testing, these tests have played a pivotal role in understanding the prevalence of the virus and implementing targeted public health measures.
Antigen Tests
Antigen tests, on the other hand, have gained popularity for their rapid results. They provide answers within minutes. Antigen tests detect particular proteins found on the surface of the virus. They offer a quick turnaround time that is important in settings like healthcare facilities or airports. However, the challenge here comes in lower sensitivity when compared to PCR tests.
Antigen tests could be less effective at detecting the virus in individuals with low viral loads or during the early stages of infection. Despite this limitation, rapid antigen tests play an important role in scenarios where immediate results are paramount, contributing to timely decision-making and isolation measures.
False Negatives and Positives
In the past two years, countries have been vigilant in the war against COVID-19, and their efforts have been fruitful. In England, most people have embraced self-testing as one of the strategies to control the spread of the virus. Whether you are self-testing or getting tested in a healthcare facility, it is important to note that no test is flawless. That’s why you need to understand the potential for false negatives and positives. Such an understanding will help you accurately interpret COVID-19 results.
Getting a false positive can make you unnecessarily anxious. It can lead to the isolation of individuals who should be going on with their day-to-day business freely. In such situations, there is a wastage of resources, especially in exercises like contact tracing and other public health interventions that may not be necessary.
On the other side, getting false negative results can be disastrous. That can lead to severe consequences whereby an infected person unknowingly spreads the virus to their contacts. There is a delicate balance between the specificity and sensitivity of the tests, that’s why Striking the right equilibrium is important to minimize the occurrence of false results and ensure the reliability of testing outcomes.
What Is the Impact of Test Timing on Accuracy
Other than knowing how to perform the tests, one of the most important factors when it comes to influencing the accuracy of tests is the timing of the test relative to the exposure or onset of the symptoms. Testing too early or too late in the infection can impact the reliability of results.
If you test early, you are more likely to get a false negative, especially if the viral load is not yet detectable. On the other hand, if you test too late, you may miss the window of peak viral shedding. Understanding the optimal timing for testing, particularly in relation to symptoms and potential exposure, enhances the accuracy of results and contributes to effective public health interventions.
Considerations for New Variants
Throughout the years, COVID-19 has had several mutations. These mutations have revolutionised how the world has been fighting against COVID-19. The emergence of new variants of the SARS-CoV-2 virus has proved to add another layer of complexity to the landscape of COVID-19, especially when it comes to testing. Some variants may have an impact on the performance of specific tests. That requires ongoing monitoring and adaptation by laboratories and test manufacturers.
As the virus continues to evolve, the scientific community remains vigilant in assessing the effectiveness of existing tests against emerging strains. This adaptability is crucial in maintaining the accuracy and reliability of testing methodologies amid the dynamic nature of the pandemic.
