(eSwab)
Swab
0.5 mL
Collection Technique:
Optimal specimens are from fresh, fluid-filled vesicles, preferably collected within three days of symptom onset.
Aspirate fluid from intact vesicles if possible, then unroof the vesicle and vigorously swab the base of the lesion to collect infected epithelial cells.
If the lesion is crusted or ulcerated, remove the crust/pus first (using saline, no antiseptics) and swab the moist base firmly.
Place the swab immediately into the transport medium, break the shaft at the score line, and cap tightly.
Storage and Transport Temperature:
Refrigerated (2–8°C): This is the optimal condition for storage and transport, and specimens are stable for up to 7 days.
Frozen (-20°C or -70°C): If transport to the laboratory is delayed for more than a few days (e.g., beyond 72 hours), the specimen should be frozen on dry ice.
Room Temperature (ambient): Avoid prolonged transport or storage at room temperature; stability is typically only 24-72 hours before quality degrades.
Heparinized specimens, tissues in optimal cutting temperature compound
Frozen
Sun-Sat
A day after collection
qPCR
Molecular
(RML)
HSV Type 1
Test
Topical Agents/Antiseptics: Application of alcohol, Betadine, creams, ointments, lotions, or anesthetics to the lesion before swabbing can inactivate the virus or inhibit the PCR reaction, leading to false negatives. Only use sterile saline to clean a lesion.
Incorrect Swab/Container: Using the wrong swab material (cotton, calcium alginate, wood shaft) is a common cause for rejection.
Inadequate Specimen: Failure to collect enough infected epithelial cells from the lesion will result in a false-negative test.
Blood Contamination: Excessive blood in the sample can inhibit the PCR reaction.
Old Lesions: The amount of viable virus or DNA decreases rapidly as lesions begin to heal or crust over, significantly reducing the sensitivity of the test.
Tissue: Transfer to a sterile container and freeze immediately.
Specimen Source: The exact anatomical source of the specimen (e.g., oral, genital, eye, CSF) is required on the requisition form for correct test processing and interpretation.
CSF Testing: PCR is the gold standard for diagnosing HSV encephalitis or meningitis, using cerebrospinal fluid (CSF) collected in a sterile container.
Blood Testing (Limited Use): HSV PCR on blood is generally only indicated for cases of suspected disseminated infection in neonates or severely immunocompromised patients, not for routine diagnosis of genital or oral herpes.
Serology Correlation: A negative PCR result, especially from an older lesion, does not rule out prior HSV infection; type-specific serological tests may be necessary in those cases to check for antibodies.
NEGATIVE
87529
87431-3
