<unk>  refers to the presence or absence of a serological marker in the blood. The presence of detectable levels of a specific marker within the serum is considered seropositivity, while the absence of such levels is considered seronegativity.
Serostatus
Limen
Order of Saint Lazarus 
Stoccareddo
Xilloc
PLOS Pathogens
Af-nest
Polyclinic