This test has just become available in Spain and has several advantages

  1. Rapid: It is as fast as the rapid antibody test, and faster than the PCR test. The results are ready from 2 hours of taking the sample (the time may vary according to the workload of the laboratory).
  2. Early detection: it can detect Covid-19 as early as 1 day after contact with an infected person, or as soon as symptoms appear until 7 days after symptoms start.
  3. Cheaper than the PCR test. It costs 85 euros.
  4. Accurate: Sensitivity is 80-94% and Specificity is >97% 
  5. It is taken by a nasal swab only (not a throat swab).

Disadvantages

  1. The result becomes negative as the infection clears (after 7 days from the start of symptoms). This may be useful to indicate that a patient is no longer infectious, but it cannot indicate a previous infection (antibody tests are better for this). 
  2. It is more expensive than the rapid antibody test which costs 65 euros.
  3. At present, it is not yet accepted for control at airports/frontiers. This may change in the future as experience with this test widens.

So, which test to have?

  1. To detect a previous infection or where the rapid antibody test is requested by an employer/for travel etc) or if cost is the imperative issue, the rapid antibody test can be done.
  2. When a PCR test is required for travel or employment, or when cost and rapidity is not an issue the PCR is recommended. At present this is the most established method for diagnosing a current active infection
  3. When cost and speed are important the new Antigen test is recommended. For example a child may be sent home from school, or an employee sent home from work with possible Covid-19 symptoms, or you have had contact with somebody who tested positive. This test can give a positive or negative result within hours, allowing that person to either isolate or get back to school/work quickly.
Categories: Uncategorised
Post by: Atlantic Clinic on 29 Sep 2020