IgG Absorption
- Before a patient's serum is tested for specific antibodies of the IgM class, antibodies of class IgG must be removed by ultracentrifugation, chromatography or immunoabsorption.
- Specifically bound IgG would displace IgM from the antigen leading to false IgM negative test results.
- Moreover, the absorption prevents any IgM class rheumatoid factors present from reacting with specifically bound IgG and thus leading to false IgM positive test results.
- Indication: an IgG absorption of serum samples should always be performed for all IgM antibody determinations in infectious serology before incubating the sera.
EUROSORB IgG/RF Absorbent for indirect immunofluorescence
- Functional principle: the EUROSORB reagent contains an anti-human IgG antibody preparation from goat. Immunoglobulin G of a serum or plasma sample is bound with high specificity by these antibodies and precipitated. If the sample also contains rheumatoid factors, these will be absorbed by the anti-human IgG/IgG complex.
- Incubation time of the sample with the reagent is 15 minutes. A centrifugation step for a subsequent investigation by immunofluorescence is recommended.
- All IgG subclasses are bound and precipitated by the anti-human IgG antibodies.
- Human serum IgG in concentrations of up to 15 mg/ml and rheumatoid factors are completely removed by the absorbent (average serum IgG concentration in adults: 12 mg/ml).
- The recovery rate of the IgM fraction is almost 100%.
- One unit contains 4.5 ml absorbent, sufficient for the absorption of 100 serum samples.
- EUROSORB IgG/RF-Absorbens.
Urea Solutions and Avidity Buffers for the Determination of Low-Avidity Antibodies in Infectious Serology
- To identify low-avidity antibodies in a patient’s serum, two immunofluorescence tests are performed in parallel: one test is carried out in the conventional way, the other one includes urea treatment between incubations with patient’s serum and peroxidase-labelled anti-human IgG, resulting in the detachment of low-avidity antibodies from the antigens.
- Low-avidity antibodies are present if the fluorescence intensity is significantly reduced (two intensity levels ore more) by urea treatment.
- The following reagents for avidity determination are available:
| IFT, Ab against |
| Order No. |
| Avidity Solution |
| Inc. Time |
Rubella | ZF 1130-0501 | urea solution, 5 M | 10 min | ||||
WNV | ZF 1130-0601 | urea solution, 6 M | 10 min | ||||
T. gondii | ZF 1130-0801 | urea solution, 8 M | 10 min | ||||
EBV-EA, EBV-CA | ZF 1130-0801 | urea solution, 8 M | 30 min | ||||
CMV | ZF 1131-0101-1 | avidity buffer 1 | 10 min | ||||
VZV | ZF 1131-0101-2 | avidity buffer 2 | 30 min |
