As of January 13, 2020, the Spectrum Health Microbiology Laboratory will switch any viral culture orders placed on cutaneous or mucocutaneous lesion specimens to molecular PCR testing as the preferred diagnostic method.
Please refer to these documents for specimen collection information and appropriate ordering codes:
Why this change?
Historically, HSV has been identified in patient specimens by performing a viral culture.
The viral culture method is:
♦ Insensitive
♦ Slow
♦ Labor intensive (involving the growth of virus within mammalian cell lines followed by immunostaining and fluorescence microscopy)
What is replacing cultures?
Molecular testing for HSV DNA is now considered to be the gold standard method for HSV detection and is the preferred diagnostic approach as discussed in current clinical guidelines.
What makes molecular testing the gold standard?
Significantly enhanced performance; including sensitivity
Results are faster
Testing is less expensive
Allows us to differentiate between HSV-1 and HSV-2 viruses
| Viral Culture | Molecular | |
| Performance | Sensitivity: 50-75% as compared to molecular
Specificity: 95+% |
Sensitivity: 95+%
Specificity: 95+% |
| Turnaround time | 2-7 days | Same day, 7 days/week |
| Patient cost | Most expensive method (CPT charges for culture plus shell vial staining) | Less expensive than culture |
| Subtype differentiation | Does not differentiate HSV-1 vs HSV-2, but can be requested as an add-on test. | Always differentiates HSV-1 vs HSV-2 |
*Despite these benefits, viral culture may still be performed on specimen types that are not FDA-approved for molecular testing.
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