Evaluation of the TGS TA system for the detection of anti-rubella antibodies

Background and aims: The aim of the present study was to evaluate the new Technogenetics TGS TA system for detecting antirubella IgG and IgM antibodies and IgG avidity. TGS TA system was compared with our routinely used system, LIAISON XL, for the detection of IgG and IgM antibodies. Only in positive IgM samples (retrospective study), TGS TA system was compared to an ELFA IgM test and with an ELISA test for the IgG avidity (if existent).
Materials and methods: Two hundred and seventy six sera samples from women were examined with TGS TA system and divided in 3 groups according to IgG and IgM screening LIAISON XL tests: 112 were of childbearing age and non-immune women (Group 1), 106 were pregnant with past infection or vaccinated (Group 2) and 49 were pregnant with positive or equivocal IgM (Group 3).
Results: The overall concordance of the IgG results between LIAISON XL and TGS TA was 93.3%: 86.6% in Group 1, 97.2% in Group 2 and 100% in Group 3. The overall concordance of the IgM results between LIAISON XL and TGS TA was 89.0%: 100% in Group 1, 100% in Group 2 and 35.6% in Group 3. In Group 3, the concordance between the results of the IgG avidity with the ELISA and TGS TA tests was 85.7%. Comparing the clinical diagnosis obtained with our protocol and that of the TGS TA system, the overall concordance was 97.4%: 86.6% in Group 1, 97.2% in Group 2 and 85.7% in Group 3.
Conclusions: TGA TS system shows to be a valuable tool with overall good clinical correlation and able to clearly identify nonspecific subjects, those with a non-recent infection or those who are vaccinated. The TGS TA test also seems to be especially sensitive in indicating vaccinated subjects with low IgG levels as immune.