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Syphilis (Treponema pallidum DNA), Qualitative Real-Time PCR
Test Code16595
CPT Codes
87798
Preferred Specimen
0.7 mL CSF collected in a plastic sterile leak-proof container or
1 genital lesion swab collected in an Aptima® Transport Tube, M4 media, VCM medium (green-cap) tube or equivalent (UTM)
1 genital lesion swab collected in an Aptima® Transport Tube, M4 media, VCM medium (green-cap) tube or equivalent (UTM)
Minimum Volume
0.3 mL CSF
Instructions
Genital lesion swab: Swab any visible lesions. Withdraw the swab without touching the skin. Immediately place the swab into the transport tube so that the tip of the swab is visible below the tube label. Carefully break the swab shaft at the score line against the side of the tube and discard the top portion of the swab shaft. Tightly screw the cap onto the tube.
Transport Temperature
Refrigerated (cold packs)
Specimen Stability
CSF
Room temperature: 7 days
Refrigerated: 14 days
Frozen: 30 days
Swab in Aptima® Transport tube
Room temperature: 21 days
Refrigerated: 14 days
Frozen: 30 days
Swab in M4, VCM (UTM)
Room temperature: Unacceptable
Refrigerated: 14 days
Frozen: 30 days
Room temperature: 7 days
Refrigerated: 14 days
Frozen: 30 days
Swab in Aptima® Transport tube
Room temperature: 21 days
Refrigerated: 14 days
Frozen: 30 days
Swab in M4, VCM (UTM)
Room temperature: Unacceptable
Refrigerated: 14 days
Frozen: 30 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Transport tubes with 2 swabs • Aptima® transport tubes with non-Aptima® swabs
Methodology
Real-Time Polymerase Chain Reaction
FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.
Setup Schedule
Set up: Mon-Sat; Report available: 2-3 days
Reference Range
Not detected
Clinical Significance
The Syphilis (Treponema pallidum) DNA, Qualitative Real-Time PCR is a molecular assay used for the direct detection of T. pallidum nucleic acid (DNA) in patient specimens to aid in the diagnosis of syphilis. Moist lesion (exudate) specimens collected during primary (and possibly secondary) syphilis can be tested in seronegative patients. Neonatal cerebral spinal fluid (CSF) can also be considered for testing as part of the laboratory evaluation in suspected cases of congenital syphilis. There is insufficient data to guide recommendations in suspected cases of adult neurosyphilis.
Molecular testing in lesion specimens from adult patients is generally used in cases where serologic results do not correlate with clinical signs and symptoms suggestive of syphilis, including seronegative patients. In neonates being evaluated for congenital syphilis, PCR testing of suspicious lesions or CSF can be considered as supplemental to other laboratory testing including nontreponemal serologic tests (eg, RPR or VDRL). This assay may provide a rapid diagnosis during primary syphilis if organism is detected. A negative PCR result does not rule out infection. PCR testing during secondary syphilis has limited value compared to serologic testing. This assay does not detect antibodies against T. pallidum and therefore should not be used in place of treponemal and nontreponemal serologic tests. Antibody testing using the traditional or reverse algorithm is still considered the primary method for screening and diagnosis of syphilis.
References:
Papp JR, et al. CDC Laboratory Recommendations for Syphilis Testing, United States, 2024. MMWR Recomm Rep. 2024 Feb 8;73(1):1-32. doi: 10.15585/mmwr.rr7301a1.
Workowski, KA. Sexually Transmitted Infections Treatment Guidelines, 2021. MMWR Recomm Rep. 2021 Jul 23;70(4):1-187.
Molecular testing in lesion specimens from adult patients is generally used in cases where serologic results do not correlate with clinical signs and symptoms suggestive of syphilis, including seronegative patients. In neonates being evaluated for congenital syphilis, PCR testing of suspicious lesions or CSF can be considered as supplemental to other laboratory testing including nontreponemal serologic tests (eg, RPR or VDRL). This assay may provide a rapid diagnosis during primary syphilis if organism is detected. A negative PCR result does not rule out infection. PCR testing during secondary syphilis has limited value compared to serologic testing. This assay does not detect antibodies against T. pallidum and therefore should not be used in place of treponemal and nontreponemal serologic tests. Antibody testing using the traditional or reverse algorithm is still considered the primary method for screening and diagnosis of syphilis.
References:
Papp JR, et al. CDC Laboratory Recommendations for Syphilis Testing, United States, 2024. MMWR Recomm Rep. 2024 Feb 8;73(1):1-32. doi: 10.15585/mmwr.rr7301a1.
Workowski, KA. Sexually Transmitted Infections Treatment Guidelines, 2021. MMWR Recomm Rep. 2021 Jul 23;70(4):1-187.
Performing Laboratory
| Quest Diagnostics Nichols Institute-San Juan Capistrano, CA |
| 33608 Ortega Highway |
| San Juan Capistrano, CA 92675-2042 |
