Diagnosis is more than performing a technical procedure! It is a multistep process and relies on good communication between clinicians or health assistants and laboratory personnel. One might differentiate the following actions:

a) The indication for a specific diagnostic test (based on a careful anamnesis and clinical examination)
b) Performing the test (under standardised conditions)
c) Interpreting the test result
d) Acting on the test result


The function of every diagnostic test is to contribute to the acceptance or rejection of a hypothetical diagnosis which has been made on the basis of demographic characteristics or disease symptoms. The result of an appropriate diagnostic test improves significantly the pre-test probability (prevalence) for the presence of an infection/disease.
Diagnostic tests are not perfect. In many cases, it is not possible to confirm or exclude an infection/disease with absolute certainty.
The performance of a test is evaluated in comparison to a reference method.