Rapid Testing Kits

Why in news?

Rapid testing kits used to detect antibodies to the novel coronavirus have proved unreliable.

Why such kits are needed?

• Governments around the world are looking for an accurate blood test that can tell people if they have immunity through past Covid-19.
• The diagnostic RT-PCR test to confirm the presence of the virus using a nasal swab in a laboratory setting is considered reliable.
• The attempts to design a rapid test that uses a blood sample to find antibodies after past infection have been proved unreliable.
• They have missed about 30% of positive cases, showing low sensitivity.

What concerns many countries?

• The low sensitivity of the kit is the phenomenon that is worrying India.
• Many Indian States have already imported several hundred thousand rapid testing kits, mainly from China.
• India’s experience is shared by the US, UK, Spain and other countries.
• ICMR has advised States to use these kits for surveillance testing rather than to make medically important decisions.

What is the challenge now?

• Narrowing down the test to reliable methods is the challenge.

• The WHO is working to identify them and the results will be crucial.
• All countries are looking at sero-surveillance as a process that may determine the status of population on Covid-19.
• An exit from lockdown and other public health measures depend on such testing.

What should India focus on?

• India should remain focused on identifying tests that work well.
• This requires close integration with efforts launched by diagnostics regulators in the U.S., Europe and China.
• These countries have allowed early use of these kits, which themselves are under evaluation.
• Some vendors of rapid testing devices in China have run afoul of regulators since they have no prior expertise in the field.
• Therefore, making purchase decisions calls for rigorous review.

What should be done?

• In the immediate context, the message should go out to States that rapid tests cannot substitute for RT-PCR to diagnose infection.
• It is by no means clear that antibodies developed in response to COVID-19 provide long-term protection against re-infection.
• A good reliable test to certify that a large section of the population have developed immunity against Covid-19 is needed.
• These tests would be a promising tool to reopen the economy with confidence.

Source: The Hindu