Description

The Diagnostic Automation, Inc. Syphilis IgG EELISA kit is a confirmatory in vitro diagnostic enzyme immunoassay for the qualitative detection of Treponema pallidum IgG antibodies in human serum or plasma. This product is not cleared by the U.S. Food and Drug Administration (FDA) for use in screening blood or plasma. This test is intended for use by clinical diagnostic laboratories as an aid in diagnosis of syphilis.

Specific, recombinant treponemal antigens are immobilized on the microplate wells. Patient samples and controls are added to the wells. Anti-treponemal antibodies, if present, will specifically bind to the immobilized antigens; all nonbound proteins are removed during the washing step. The antigen-antibody complex is subsequently reacted with antihuman
IgG antibodies conjugated with horseradish peroxidase (HRPO). After a second wash, which removes the unbound conjugate, a chromogenic reaction takes place on the plate as a result of addition of the TMB, a substrate for the peroxidase. The resulting colour is measured spectrophotometrically after adding stop solution. Colour intensity is proportional to the amount of antibody present in the patient\\\'s sample.

In response to Treponema pallidum subspecies pallidum, the causative agent of syphilis, two types of antibody responses normally result: non-specific (anti-cardiolipin) and specific (anti-treponemal). While non-specific antibodies occur in the majority of infectees, many other conditions can give rise to false positive results, yielding an overall specificity of about 50% in the general population.

One of the major reasons for the continued use of non-specific tests (RPR, VDRL, Wasserman etc.) is based on the observation that in response to appropriate (antibiotic) treatment, a significant decrease in titer usually takes place which is taken as the criterion of adequate treatment.

Treponemal or specific tests are based on the use of treponemal antigens in the assay. Prior to the HIV era, treponemal tests were largely used to confirm positive results obtained by non-specific screen tests. Although older treponemal tests (such as MHA-TP and FTA-Abs) are generally considered reliable for past and current infection (regardless of treatment) their specificity is limited due to the absence of in vitro culture techniques for T. pallidum. The use of recombinant treponemal antigens in \\\"DAI\\\" results in increased sensitivity and specificity. Unless applied during early primary syphilis, treatment does not significantly affect the treponemal antibody status; hence no assumptions about efficacy of treatment or staging of disease can be made.

The results of the assay are to be used as an aid in diagnosis. Positive samples should be verified by confirmatory tests such as MHA-TP and/or FTA-Abs. Except for areas where non-venereal trepanematoses are endemic, positive Diagnostic Automation results is usually the result of a syphilitic infection.

This test contains material of human and animal origin and should be handled as a potential carrier or transmittance of disease. All reagents supplied are strictly for in vitro use only.