Table 5.2.

Diagnostic tests for EBV infections

Test	Advantages	Disadvantages	Proportion of Patients Positivea	Median Day Detected after Onset of Illness (range of days until detection) a
Heterophile antibody	Inexpensive, easy to perform, becomes negative 3–12 months postinfection	Nonspecific (false positives due to acute infections and autoimmune diseases); may be negative during first week of illness and persistently negative in young childrenb	85% (72% the first week)	0 (-6–31)
VCA IgM antibody	Specific, becomes negative 3–12 months postinfection	Not usually performed at point of care sites	95% (85% the first week)	2 (-21–20)
VCA IgG antibody	Best test for diagnosis of past EBV infection	Not usually performed at point of care sites	100%	31 (1–118)
EBNA-1 IgG antibody	Best test to distinguish acute from convalescent EBV infection	Not usually performed at point of care sites; 5–10% of patients never become positive	90–95%	91 (6–479)
EA antibody	A marker of acute infection	Absent in 20–40% of acute illnesses; persists for years in ~20% of cases	Not tested	Not tested
Immunoblot antibodies	Can be used to stage infection (acute, convalescent, past)	Relatively expensive	100%c	2 (-25–60)
Blood viral load	Correlates with severity of illness; best test to monitor infection in the immuncompromised host	Viremia is short-lived and may be missed in immunocompetent patients	80%	4 (-8–38)
Oral viral load	Non-invasive, confirms past infection	Cannot be used to diagnose acute infection because virtually all antibody-positive adults shed oral virus intermittently	100%	-4 (-21–31)

^aBased on prospective studies of EBV-naive college students who developed primary EBV infections (Balfour et al. 2005; Balfour et al. 2013a; Balfour et al. Unpublished observations.

^bAlthough heterophile tests are most commonly used to diagnose infectious mononucleosis, the CDC has recently advised against them “for general use.”(Centers for Disease Control and Prevention 2014).

^cTo one or more antigens.