How to calculate the probability of an infected person?

How to calculate the probability of an infected person?

Since 99 % of the tests on infected people is positive, then 1 % is negative. Similarly, we can conclude that 98 % of the tests in not infected people is negative. Where P I means person is infected and T P means tests are positive. Now, we know p ( P I), that is 0.5 100 = 0.005, and we also know p ( T P ∣ P I) = 99 100 = 0.99.

How can you tell if you have a past infection?

Learn more Antibody or serology tests look for antibodies in your blood to determine if you had a past infection with the virus that causes COVID-19. Antibodies are proteins created by your body’s immune system soon after you have been infected or vaccinated.

Is it possible to get a negative test for a past infection?

You could have a current infection or been recently infected. The test may be negative because it typically takes 1–3 weeks after infection for your body to make antibodies. It’s possible you could still get sick if you have been exposed to the virus recently. This means you could still spread the virus.

What is the probability of a positive virus test?

A diagnostic test for the identification of the virus is positive in 99 % for infected people and in 2 % for not infected people. Please estimate the probability that a person whose test was positive is infected with the virus. And this is my solution.

Learn more Antibody or serology tests look for antibodies in your blood to determine if you had a past infection with the virus that causes COVID-19. Antibodies are proteins created by your body’s immune system soon after you have been infected or vaccinated.

Can a doctor not identify the cause of an infection?

If the right test is not done, doctors may not identify the cause of infection. When a microorganism is identified, doctors can then do tests to determine which drugs are most effective against it ( susceptibility tests ), and effective treatment can be started sooner.

You could have a current infection or been recently infected. The test may be negative because it typically takes 1–3 weeks after infection for your body to make antibodies. It’s possible you could still get sick if you have been exposed to the virus recently. This means you could still spread the virus.

Can a antibody test be used to diagnose a current infection?

Antibody tests should not be used to diagnose a current infection with the virus that causes COVID-19, except in instances in which viral testing is delayed. An antibody test may not show if you have a current infection because it can take 1–3 weeks after the infection for your body to make antibodies.