Sensitivity and Specificity

The sensitivity of SARS-CoV-2 rapid tests explained:

The sensitivity of SARS-CoV-2 rapid tests describes the likelihood of a positive test result that is correctly identified as positive.

Sensitivity therefore tells you how likely you are to get a positive test result if you are actually positive.

Example of use: The sensitivity of a rapid test is approximately 96.5%. This means:

• at 96.5% you get a positive test result and are also really positive.
• to 3.5% you get a positive test result but are actually negative (false-positive result).

This is the reason why positive test results should always be checked with a more accurate PCR test in the laboratory.

The specificity of SARS-CoV-2 rapid tests simply explained.

The specificity of tests describes the probability that a negative test result is actually negative. So specificity says: how likely you are to get a negative test result and actually be negative.

Example of use: The specificity of a rapid antigen test is approximately 99.7%. This means:

• 99.7% of the test results are negative and really negative.
• to 0.3% you then get a negative test result, but are actually positive (false negative result). As you can see, the specificity of a rapid antigen test is very good, which is why retesting is not usually recommended here.

The mean value as test accuracy

The mean value of sensitivity and specificity is often summarised as test accuracy. It is important to actually look at both values when choosing a particular test.

Example of use: If the sensitivity of an antigen test is 96.5% and the specificity is 99.7%, the test accuracy is 98.1%.

• 99.7% of the test results are negative and really negative.
• to 0.3% you then get a negative test result, but are actually positive (false negative result). As you can see, the specificity of a rapid antigen test is very good, which is why retesting is not usually recommended here.

The mean value as test accuracy

The mean value of sensitivity and specificity is often summarised as test accuracy. It is important to actually look at both values when choosing a particular test.

Example of use: If the sensitivity of an antigen test is 96.5% and the specificity is 99.7%, the test accuracy is 98.1%.

• 99.7% of the test results are negative and really negative.
• to 0.3% you then get a negative test result, but are actually positive (false negative result). As you can see, the specificity of a rapid antigen test is very good, which is why retesting is not usually recommended here.

The mean value as test accuracy

The mean value of sensitivity and specificity is often summarised as test accuracy. It is important to actually look at both values when choosing a particular test.

Example of use: If the sensitivity of an antigen test is 96.5% and the specificity is 99.7%, the test accuracy is 98.1%.

• 99.7% of the test results are negative and really negative.
• to 0.3% you then get a negative test result, but are actually positive (false negative result). As you can see, the specificity of a rapid antigen test is very good, which is why retesting is not usually recommended here.

The mean value as test accuracy

The mean value of sensitivity and specificity is often summarised as test accuracy. It is important to actually look at both values when choosing a particular test.

Example of use: If the sensitivity of an antigen test is 96.5% and the specificity is 99.7%, the test accuracy is 98.1%.

• 99.7% of the test results are negative and really negative.
• to 0.3% you then get a negative test result, but are actually positive (false negative result). As you can see, the specificity of a rapid antigen test is very good, which is why retesting is not usually recommended here.

The mean value as test accuracy

The mean value of sensitivity and specificity is often summarised as test accuracy. It is important to actually look at both values when choosing a particular test.

Example of use: If the sensitivity of an antigen test is 96.5% and the specificity is 99.7%, the test accuracy is 98.1%.