Question

Which of the following is the least accurate statement about screening for COVID-19

            A. RT-PCR testing is the most accurate diagnostic test for COVID-19 in terms of sensitivity and specificity

            B. The best test to use for COVID-19 depends on whether the goal is individual    diagnosis or screening for ability to transmit COVID-19

            C. Frequent repetition of antigen tests has the potential to detect those who are able to transmit COVID-19

            D. Antigen tests are the most accurate test for COVID-19 in terms of sensitivity and specificity

Answer 1

HERE THE ANSWER IS OPTION D.

OPTION D which is 'Antigen tests are the most accurate test for COVID 19 in terms of sensitivity ans specificity is a FALSE statement.

Antigen test provides results faster than molecular tests(rt-pcr), but they have a higher chance of missing an active infection.The specificity to discover true positive is between 50.6% to 80 %. Therefore negative results from an antigen test may need to be confirmed with a rt-pcr test.

Other options

RT-PCR tesrs are the operational gold standard for detecting COVID 19 .They have a sensitivity and specificity of greater than 95%.

The choice of type of test , whether molecular or antigen test should be made in the grounds of whether it is for individual diagnosis or screening of a large population.Since the specificity of antigen test is less, a negative antigen tesrt should be followed by molecular test.

An antigen test reveals if a person is currently infected with COVID 19.Once the infecton is gone, the antigen disappears. So it can be used for identifying people, who can transmit the infection.