Diagnostic gap
The diagnostic gap , also: diagnostic window (English window period , diagnostic gap ), describes in medicine the period of time that elapses between an infection and the point in time from which the previous or current presence of a pathogen in an organism is determined by a specific test can be reliably proven.
The diagnostic gap occurs, among other things, in the determination of a pathogen , in epidemiology , in the control of infectious diseases , in safer sex measures as well as in blood and organ donations , since an infected person is not discovered as such during this period, but still infect other people. A diagnostic gap always relates to a single pathogen in a specific host with specific, previously defined detection methods.
Emergence
A diagnostic gap arises when the analyte to be detected (e.g. virus particles or disease-specific antibodies ) is not immediately available in sufficient concentration to be detectable with a pathogen detection or the detection of an immune response . This includes both the eclipse following the infection and the three to seven days required for the adaptive immune response to develop measurable amounts of antibodies and cytotoxic T cells .
With the common ELISA test for the detection of antibodies after an HIV infection, for example, it takes 12 weeks before the body has produced so many antibodies that there is a 99 percent probability that the test will be positive. If the test is carried out before the 12-week period (after the alleged infection), a false negative result must be expected.
The formation of specific antibodies against pathogens or pathogen components (e.g. during vaccination ) is also referred to in technical terms as seroconversion .
Demarcation
The diagnostic gap is sometimes mistakenly equated with the incubation period , i.e. the period between infection and the first appearance of symptoms .