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Test Code HHV6V Human Herpesvirus-6, Molecular Detection, PCR, Spinal Fluid

Reporting Name

HHV-6 PCR, Varies

Useful For

As an adjunct in the rapid diagnosis of human herpesvirus-6 infection using cerebrospinal fluid specimens

 

This test should not be used to screen asymptomatic patients.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

CSF


Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Container/Tube:

Preferred: Aliquot tube

Acceptable: Sterile vial

Specimen Volume: 0.5 mL

Collection Instructions: Collect specimen from second collection vial. Do not centrifuge.


Specimen Minimum Volume

0.3 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
CSF Refrigerated (preferred) 7 days
  Frozen  7 days

Reference Values

Negative

Day(s) Performed

Monday, Wednesday, Friday

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

87532

LOINC Code Information

Test ID Test Order Name Order LOINC Value
HHV6V HHV-6 PCR, Varies 33942-4

 

Result ID Test Result Name Result LOINC Value
SS012 Specimen Source 31208-2
56092 HHV-6 PCR, Varies 33942-4

Clinical Information

Human herpesvirus-6 (HHV-6) is a member of the Herpesviridae family. These viruses contain DNA surrounded by a lipid envelope. Among members of this group, this virus is most closely related to cytomegalovirus (CMV) and HHV-7. As with other members of the herpesvirus group (herpes simplex virus [HSV] 1, HSV 2, varicella-zoster virus, CMV, Epstein-Barr virus, HHV-7, HHV-8), HHV-6 may cause primary and reactivated infections subsequent to latent association with cells.(1) Infection with HHV-6 occurs early in childhood. Most adults (80%-90%) have been infected with this virus.

 

HHV-6 was first linked with exanthem subitum (roseola infantum) in 1998; since then, the virus has been associated with central nervous system disease almost exclusively in patients who are immunocompromised.(1) HHV-6 is commonly detected in patients posttransplantation. Clinical symptoms associated with this viral infection include febrile illness, pneumonitis, hepatitis, encephalitis, and bone marrow suppression. However, the majority of HHV-6 infections are asymptomatic.(2) The incidence of HHV-7 infection and its clinical manifestations posttransplantation are less well characterized.

 

HHV-6 is designated as variant A (HHV-6A) or variant B (HH6-B) depending on restriction enzyme digestion patterns and its reaction with monoclonal antibodies. Generally, variant B has been associated with exanthem subitum, whereas variant A has been found in many immunosuppressed patients.(3)

Method Description

Viral nucleic acid is extracted by the MagNA Pure automated instrument (Roche Applied Science) from clinical specimens. Primers directed to the immediate early gene of human herpesvirus-6 (HHV-6) produce a 195 base pairs amplicon. The LightCycler instrument (Roche Applied Science) amplifies and monitors the development of target nucleic acid sequences after the annealing step during polymerase chain reaction (PCR) cycling. This automated PCR system can rapidly (1 hour) detect amplicon development through stringent air-controlled temperature cycling and capillary cuvettes. The detection of amplified products is based on the fluorescence resonance energy transfer (FRET) principle. For FRET product detection, a hybridization probe with a donor fluorophore, fluorescein, on the 3'-end is excited by an external light source and emits light that is absorbed by a second hybridization probe with an acceptor fluorophore, LC-Red 640, at the 5'-end. The acceptor fluorophore then emits light of a different wavelength that can be measured with a signal that is proportional to the amount of specific PCR product. LightCycler hybridization probes are designed for exact homology to HHV-6.(Cockerill FR III, Uhl JR: Applications and challenges of real-time PCR for the clinical microbiology laboratory. In: Reischel U, Wittwer C, Cockerill F. Rapid Cycle Real-Time PCR - Methods and Applications. Springer-Verlag; 2002:3-30)

Reject Due To

  All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Method Name

Real-Time Polymerase Chain Reaction (PCR)/DNA Probe Hybridization

Forms

If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.

Secondary ID

89888

Interpretation

A positive result indicates the presence of specific DNA from human herpesvirus-6 (HHV-6) and supports the diagnosis of infection with this virus.

 

A negative result indicates the absence of detectable DNA from HHV-6 in the specimen, but it does not negate the presence of the virus or active or recent disease.