MRL Diagnostics and Meridian Diagnostics have recently designed herpes simplex virus type 2 (HSV-2)-specific enzyme immunoassays for HSV-2 antibody detection. Blood donor sera were assayed for HSV-2 antibodies by both methods. The sensitivity, specificity, and efficiency were 97.9, 95.4, and 95.9% for the MRL assay and 83.2, 98.2, and 95.5% for the Meridian assay, respectively.Detection of disease caused by herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) has been complicated by the lack of availability of consistently good diagnostic testing. Although culture is definitive in making a diagnosis, the timing of culture is critical for success. Culture during periods of active disease produces optimal recovery rates (6, 8). Reliance on culture for the detection of genital ulcer disease caused by herpes simplex viruses may result in underdiagnosis of the condition (7). Direct antigen detection techniques are not reliable since they appear to be only 50% as sensitive as optimal viral isolation procedures (5). Although PCR detection of viral shedding has been described as a much more sensitive method than culture for the detection of viral shedding, this method is not currently available for clinical diagnosis (2). Supplementing culture with direct fluorescent antibody staining specific for HSV-1 or HSV-2 may yield a diagnosis even when the culture is negative (12), but many institutions do not offer this method of diagnostic testing. Other diagnostic tests, including Pap smears, Giemsa-stained preparations, and many of the point-of-care antigen detection assays, do not differentiate between HSV-1 and HSV-2 infections. Since the type of HSV implicated in disease has ramifications for prognosis (9,14), it is important to specify the HSV subtype.Early application of type-specific serologic testing for HSV-1 and HSV-2 has been shown to be of benefit in testing firsttime, recurrent, and asymptomatic infections as a means to definitive diagnosis and appropriate patient and spouse counseling (10). A seronegative status may be seen in patients with acute infection or in those at risk for acquiring infection, while a seropositive status is seen in patients with latent or recurrent infections. Until recently, enzyme immunoassays (EIAs) utilized either whole virus antigen preparations or type-specific antigenic determinants with extensive HSV-1 and HSV-2 immunologic response cross-reactivity (4). Since HSV-1 and HSV-2 share many common antigenic determinants (11, 13), these assays cannot be used reliably to differentiate HSV-1-from HSV-2-infected individuals. Western blot assays, although capable of differentiating antibodies against HSV-1 and -2, are expensive and are not readily available to most clinical laboratories (1). The identification of type-specific glycoproteins G1 (gG1; HSV-1-specific antigen) and G2 (gG2; HSV-2-specific antigen) led to the development of bulk protein production for type-specific assays. Recently, two manufacturers, MRL Diagnostics Inc. (Cincinnati, Ohio) and Meridian Diagnostics (Cypress, C...

Two companies, MRL and Meridian Diagnostics, have developed Food and Drug Administration-approved herpes simplex virus type 1 type-specific enzyme immunoassays. The sensitivity, specificity, and overall testing efficiency of these assays were 98.2, 93.8, and 96.6% for MRL and 98.8, 99.0, and 98.1% for Meridian, making both of these kits suitable for use in the clinical lab.The herpes simplex viruses (herpes simplex virus type 1 [HSV-1] and HSV-2) are important causes of disease worldwide. HSV-1 is the primary cause of oral-facial and pharyngeal herpes infections and may cause herpetic whitlow, eye infections, and disseminated disease (1,2,8,15). HSV-1 also accounts for 10 to 15% of all genital herpetic infections (3, 6, 11). The proportion of genital infections with HSV-1 is reportedly even higher in some locations (4, 10, 13).Transmission of HSV-1 occurs following contact with fluid from vesicular lesions or contact with infected body fluids, such as saliva and genital secretions (4,8,9). Although HSV-1 has historically been acquired primarily in childhood, acquisition of the virus is now often seen during early adulthood (4,8,9). Seroprevalence studies from several sites worldwide have indicated that approximately 60 to 70% of adolescents have not developed antibodies to this virus and are therefore still susceptible to infection with HSV-1 (5, 7, 8).HSV-1 serostatus is also important with regard to the vaccine developed for HSV-2. The usefulness of the vaccine appears to be linked to the HSV-1 serostatus of the individual being immunized. Only female recipients with a negative HSV-1 serostatus prior to immunization appear to derive benefit from this vaccine (S. Spruance and The Herpes Vaccine Efficacy Study Group, Abstr. Addendum 40th Intersci. Conf. Antimicrob. Agents Chemother., abstr. L-6, p. 22, 2000). This, coupled with the role of HSV-1 as a significant etiologic agent for herpes genitalis, produces the need for a reliable HSV-1 immunoglobulin G (IgG) type-specific assay. This report focuses on the head-to-head comparison of two Food and Drug Administration (FDA)-approved HSV-1 type-specific EIAs.Serum from 532 blood donor specimens was collected from the Central Kentucky Blood Center, Lexington, Ky., and frozen in 2-ml aliquots at Ϫ70°C until testing. Serologic evaluation of HSV-1 antibodies was performed using glycoprotein G type-specific enzyme immunoassays from Meridian Diagnostics Inc. (Cincinnati, Ohio) and from MRL Diagnostics (Cypress, Calif.). All testing was performed according to the manufacturers' specifications. Absorbances were read on an automated ELx800 Universal Microplate Reader (Bio-Tek Instruments Inc.) at 405 nm for the Meridian assays and 450 nm for the MRL assays. For both manufacturers, absorbency cutoff values were those established by validation studies with a mean absorbency value: those with Ͼ0.99 times the reference absorbency were interpreted as positive, those with 0.91 to 0.99 times the reference absorption were interpreted as equivocal, and those with less than 0.91 time...