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Test ID: VDRL Screen CSF
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VDRL Antigen
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Useful For
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Qualitative and semi quantitative non-treponemal flocculation test for the detection of reagin antibodies in human CSF. CSF-VDRL is primarily performed when neurosyphilis is suspected.
The diagnosis of neurosyphilis is based on the combination of clinical and laboratory findings, including neurological signs and symptoms, reactive serum syphilis serology, CSF cell count, CSF protein level, and reactive CSF-VDRL. The test of CSF-VDRL should not be interpreted as a standalone diagnostic test.
In newborns, CSF-VDRL may be performed as part of the evaluation of confirmed or highly probable congenital syphilis, particularly when central nervous system involvement is suspected. The decision to perform CSF-VDRL for suspected congenital syphilis should take into consideration:
- Maternal syphilis history and treatment status.
- Newborn clinical findings consistent with congenital syphilis.
- A neonatal serum RPR titer ≥4-fold higher than the maternal titer at delivery.
- Other relevant laboratory or radiological findings.
Note: CSF-VDRL testing will only be performed after serum syphilis serology has been tested and confirmed Reactive.
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Method name and description
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Aliases
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Neurosyphilis, Congenital syphilis
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Specimen type / Specimen volume / Specimen container
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Specimen type: CSF
Specimen volume: 1-2 mL
Specimen container: Sterile container
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Collection instructions / Special Precautions / Timing of collection
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C Collection by lumbar puncture as per organization guidelines
No special precautions / No timing of collection
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Storage and transport instructions
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Maintain specimen at 2-8°C
The specimens should be transported to Virology Section in cold box immediately
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Specimen Rejection Criteria
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Quantity of sample not sufficient
Mixed with blood
Wrong container
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Biological reference intervals and clinical decision values
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Non-Reactive: Indicates that the sample tested does not contain reagin antibodies.
Reactive: Indicates that the sample tested contains reagin antibodies
Reactive with titer (e.g. 1:2; 1:4; 1:8; 1:16; 1:32), indicates the highest dilution that showed a reactive result.
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Factors affecting test performance and result interpretation
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- Biological false-positive VDRL results may occur, particularly in individuals with drug abuse or conditions such as systemic lupus erythematosus (SLE), malaria, vaccinia, infectious mononucleosis, leprosy, viral pneumonia, and after smallpox vaccination.
- Samples should be free from bacterial contamination, gross hemolysis or lipemia.
- Only CSF and serum is suitable for use in this test. Plasma is not acceptable.
- Samples should be stored in the original tube at 2–8°C for up to 4 hours. For longer storage, the serum should be separated and stored at 2–8°C for up to 5 days or at –20°C for long-term storage.
- Repeated freezing and thawing of specimens should be avoided.
- A prozone effect may occur in samples with high antibody concentrations, causing weak or false-negative VDRL results; therefore, weakly reactive or nonreactive samples should be tested quantitatively to determine the true endpoint.
- Pinta, yaws, bejel and other treponemal diseases produce positive reactions in this test.
- The results of the VDRL Test must be confirmed by a treponemal test for reactive serum samples.
- A final diagnosis should not be made on the result of a single test but should be based on a correlation of test results with other clinical findings.
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Turnaround time / Days and times test performed / Specimen retention time
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Turnaround time: within 48 hours
Days and times test performed: The sample is tested on the day of receipt or on the following day
Specimen retention time: 2 weeks.
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