EBV Monospot

Question 1

Heterophile antibody tests, including monospot tests

What is the basic mechanism of the test?

Answer 1

red cell agglutination assay

detect anti-red cell antibodies produced as part of polyclonal antibody response during EBV infection. B-cells become activated after infection, and produce antibodies at rapid rate, which are not specific to the virus, but rather to an assortment of targets including red cells

rapid and cheap

in correct patient group, can have high sensitivity and specificity.
A positive result in patient with EBV symptoms, has a very high PPV for having EBV infection

Question 2

What are other reasons for positive heterophile antibody tests?

Answer 2

other viral infection

autoimmune disease

haematological infection

Question 3

What are complications of EBV infection?

Answer 3

Immediate:
splenic rupture
beta-haemolytic strep infections

Later:
Nasopharyngeal carcinoma
Lymphoma

Associations:
Chronic fatigue syndrome
Multiple sclerosis

Question 4

How soon are heterophile antibodies detectable?

How long do they persist for?

Answer 4

detectable 2-5 weeks after infection

can be present for >1 year

Question 5

What is the PPV and NPV for heterophile antibody testing?

Answer 5

in correct patient group, can have high sensitivity and specificity.
A positive result in patient with EBV symptoms, has a very high PPV for having EBV infection

Low NPV - as there are other causes of positive heterophile test