Method Description

Neurosyphilis Screen, IgG, Spinal Fluid

The test kit contains microtiter strips with break-off reagent wells coated with purified recombinant Treponema pallidum antigens. In the first reaction step, diluted patient samples are incubated in the wells. In the case of positive samples, T pallidum-specific IgG antibodies will bind to the antigens. To detect the bound antibodies, a second incubation is carried out using an enzyme-labelled antihuman IgG (enzyme conjugate), followed by a third incubation using chromogen/substrate, which catalyzes a color reaction that is then measured for optical density (OD) using spectrophotometry.(Package insert: Antibodies of the IgG class against Treponema pallidum in cerebrospinal fluid. Euroimmun Ag; 12/2012)

Neurosyphilis IgG Antibody Index

The test kit contains microtiter strips with break-off reagent wells coated with purified recombinant T pallidum antigens. In the first reaction step, diluted patient samples are incubated in the wells. In the case of positive samples, T pallidum-specific IgG antibodies will bind to the antigens. To detect the bound antibodies, a second incubation is carried out using an enzyme-labelled antihuman IgG (enzyme conjugate), followed by a third incubation using chromogen/substrate, which catalyzes a color reaction that is then measured for optical density (OD) using spectrophotometry. The obtained OD values of the paired patient serum and cerebrospinal fluid (CSF) samples are compared against a 4-level calibration curve to quantitatively determine the relative anti-T pallidum IgG antibody titers.(Unpublished Mayo method)

The quantitative test results obtained on paired serum and CSF specimens using the T pallidum IgG enzyme-linked immunosorbent assay are expressed as relative units (U/mL) and must be used along with the total IgG and albumin levels in the patient's paired serum and CSF samples to calculate the anti-T pallidum antibody index (AI), which determines the absence or presence of intrathecal anti-T pallidum IgG antibody synthesis. Total IgG and albumin testing on serum and CSF is performed using the Siemens BN II nephelometric testing system.(Instruction manual: Siemens Nephelometer II Operations. Siemens V 2.3, 2008; Addendum to the Instruction Manual 2.3, 08/2017)

To detect an infection of the central nervous system, it is necessary to differentiate between intrathecally produced antibodies and antibodies passed from blood into the CSF. The AI is the value of intrathecal pathogen-specific antibody production. This AI value represents the portion of pathogen-specific antibodies in total IgG of CSF and the portion of pathogen-specific antibodies in total IgG of serum. The patient's AI is calculated using the Reiber and Lange method.(Reiber H, Lange P. Quantification of virus-specific antibodies in cerebrospinal fluid and serum: sensitive and specific detection of antibody synthesis in brain. Clin Chem. 1991;37(7):1153-1160)

VDRL Titer, Spinal Fluid

The VDRL antigen and spinal fluid are mixed on a 180 RPM rotator. The antigen, a cardiolipin-lecithin coated cholesterol particle, flocculates in the presence of reagin.(US Department of Health, Education and Welfare, National Communicable Diseases Center, Venereal Disease Program. Manual of Tests for Syphilis. Centers for Disease Control; 1969; Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Elsevier; 2020)

Neurosyphilis IgG Spinal Fluid Screen Technical Interpretation

Automated interpretation of spinal fluid IgG antibody screening results for neurosyphilis.