Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1380 page)

HERPES SIMPLEX VIRUS (HSV) SEROLOGY TESTS, TYPE 1 AND TYPE 2–SPECIFIC ANTIBODIES, IgG AND IgM

   Definition

   HSV is a common STD worldwide. Although HSV type 2 (HSV-2) remains the main causative agent for the preponderance of virologically confirmed infections, HSV type 1 (HSV-1) is associated with an increasing proportion of cases of genital herpes.

   HSV-1 generally infects the mucous membrane of the eye, mouth, and mucocutaneous junctions of the face, and it is also one of the most common causes of severe sporadic encephalitis in adults.

   HSV-2 is usually associated with mucocutaneous genital lesions. Recently, an increasing number of genital herpes infections have been shown to be due to HSV-1. HSV-1 causes primary episodes indistinguishable from HSV-2, but with less frequent recurrence.

   Pregnant women who develop genital herpes near the time of delivery are at high risk for transmission to the neonate. Transmission of HSV infection to neonates is associated with high morbidity and mortality rates if untreated.

   Because HSV-1 and HSV-2 share common antigenic determinants, antibody detected against one viral type may cross-react with the other viral type. Truly type-specific antibody tests are based on glycoprotein G1 (from HSV-1) and glycoprotein G2 (from HSV-2), as these proteins exhibit very limited homology. The CDC recommends the use of type-specific glycoprotein G based assays when serology is performed.

   Other names: Herpes simplex serology, HSV antibody titer.

   
Normal range:
Negative.

   Use

   To diagnose a patient with a history of genital lesions who did not have a diagnostic workup, diagnose a past or present HSV infection in a patient with an atypical presentation, determine susceptibility of a sexual partner of a patient with documented genital HSV infection, and identify asymptomatic HSV infection in pregnant women who are at risk for shedding at the time of delivery with potential transmission to the infant or help predict the risk of recurrence.

   Interpretation

   HSV IgM–combined positive result (i.e., the presence of IgM class HSV 1 and/or 2 antibodies) indicates recent infection. The presence of HSV 1 and/ or 2 antibodies may indicate a primary or reactivated infection but cannot distinguish between them.