Antigénantitest

Antigénantitest is a diagnostic test designed to detect specific antigens, usually proteins, from a pathogen in a patient specimen. It is used to determine active infection by organisms such as viruses or bacteria and is distinct from molecular tests that detect genetic material and from serological tests that detect host antibodies.

Most antigénantests are immunoassays that use antibodies to capture and identify target proteins. Many rapid antigénantests employ a lateral flow immunoassay format, where a test strip yields a visible indication within minutes. Some antigénantests require laboratory equipment or instrumentation, while others are designed for point-of-care use outside specialized laboratories.

Common specimen types include nasal or nasopharyngeal swabs, though saliva-based tests also exist for certain pathogens. Antigénantests generally perform best when the pathogen’s antigen level is high, such as during the early phase of symptomatic infection. They are valued for their speed, simplicity, and lower cost compared with molecular methods.

Performance characteristics vary by test and pathogen. Sensitivity (the ability to detect infection) is generally lower than that of RT-PCR and is influenced by viral-load, sampling quality, and timing relative to onset of illness. Specificity (the ability to avoid false positives) is typically high but can be affected by cross-reactivity. Positive results in high-prevalence settings are usually reliable, while negative results may require confirmation with a molecular test if clinical suspicion remains high or if testing occurs late or with poor sampling.

Antigénantests are widely used for rapid screening in clinics, schools, workplaces, airports, and outbreak situations, especially when quick results are needed. They complement molecular and serological testing and are an important tool in infection control, though their limitations must be considered in interpretation.