Blood tests for H pylori can only tell if your body has H pylori antibodies. It cannot tell if you have a current infection or how long you have had it
Serological or serodiagnostic tests for TB means diagnosing TB through looking at a blood sample, and specifically looking for antibodies in the blood sample
A positive test for CMV IgG indicates that a person was infected with CMV at some time during their life but does not indicate when a person was infected
Detection of specific IgM antibodies in a serum sample collected within the first few days after rash onset can provide presumptive evidence of a current or recent rubella virus infection