Herpes Simplex Virus (HSV), Molecular Detection, PCR
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Herpes simplex virus (HSV) causes various clinical syndromes. Anatomic sites infected include skin, lips, oral cavity, eyes, genital tract, and central nervous system (CNS). Systemic involvement may also occur.
Fresh brain tissue is the definitive specimen for detection of HSV from patients with CNS disease. However, because brain biopsy is an invasive procedure, it is infrequently performed for laboratory diagnosis. Similarly, it is difficult to recover HSV from cerebrospinal fluid (CSF) specimens in culture systems, and the serologic diagnosis of HSV CNS disease has not been informative during early onset disease. HSV PCR detection from CSF is a sensitive and specific alternative for detection of disease involving the CNS, as well as oral, genital, ocular, and other sites.
Aiding in the rapid diagnosis of herpes simplex virus (HSV) infections, including qualitative detection of HSV DNA in cerebrospinal fluid and other (non-blood) clinical specimens
Qualitative detection of HSV DNA
This is a qualitative assay; results are reported either as negative or positive for herpes simplex virus (HSV) type 1 or HSV type 2, or HSV indeterminate.
Detection of HSV DNA in clinical specimens supports the clinical diagnosis of infection due to the virus. The lower limit of detection of LightCycler PCR is 10 copies DNA target per microliter. HSV DNA is not detected in cerebrospinal fluid from patients without central nervous system disease caused by this virus.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
A negative result does not eliminate the possibility of herpes simplex virus (HSV) infection. HSV DNA may not be detectable in the early acute stages of the central nervous system disease. In addition, in some cases, after initial detection (positive result), HSV DNA may only be present in cerebrospinal fluid (CSF) for 3 to 4 weeks after initial presentation of symptoms. DNA levels may fall to undetectable with time.
Although the reference range is typically "negative" for this assay, this assay may detect viral shedding in asymptomatic individuals. This may be especially relevant when dermal or genital sites are tested, since intermittent shedding without noticeable lesions has been described.(1) CSF DNA is not expected to contain detectable HSV DNA in patients without related disease. This assay is only to be used for patients with a clinical history and symptoms consistent with HSV infection, and must be interpreted in the context of the clinical picture. This test should not be used to screen asymptomatic patients.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Clinical References Provides recommendations for further in-depth reading of a clinical nature
1. Schiffer JT, Corye L: New concepts in understanding genital herpes. Curr Infect Dis Rep Nov 2009;11(6):457-464
2. Espy MJ, Uhl JR, Svien KA: Laboratory diagnosis of herpes simplex virus infections in the clinical laboratory by LightCycler PCR. J Clin Microbiol 2000;38(2):795-799
3. Espy MJ, Ross TK, Teo R: Evaluation of LightCycler PCR for implementation of laboratory diagnosis of herpes simplex virus infections. J Clin Microbiol 2000;38(8):3116-3118
4. Sauerbrei A, Eichhorn U, Hottenrott G, Wutzler P: Virological diagnosis of herpes simplex encephalitis. J Clin Virol 2000;17(1):31-36
5. Mitchell PS, Espy MJ, Smith TF, et al: Laboratory diagnosis of central nervous system infections with herpes simplex virus by PCR performed with cerebrospinal fluid specimens. J Clin Microbiol 1997;35(11):2873-2877
6. Yi-Wei T, Mitchell PS, Espy MJ, et al: Molecular diagnosis of herpes simplex virus infections in the central nervous system. J Clin Microbiol 1999;37(7):2127-2136