This private reference-level blood test provides a complete Toxoplasma gondii antibody evaluation, combining IgM, the Sabin-Feldman dye test and IgG avidity. The catalogue price is £195.00 plus a £50 phlebotomy fee, with results in 10 days.
IgG avidity helps distinguish a long-standing past immunity from a recent primary infection, which is particularly important during pregnancy or before conception.
Written by Mr Stephen Lingam. Reviewed by Dr Hikmat Naoum (GMC 3047637) on 18/10/2026.
High IgG avidity indicates that infection occurred at least 3 to 4 months before the sample was taken, helping reassure pregnant patients when a screening IgM is equivocal or positive.
It is the reference neutralisation assay used by specialist toxoplasma reference laboratories to confirm true Toxoplasma antibodies.
No fasting is required. A single venous blood draw at 117a Harley Street covers all three components of the evaluation.
Because samples undergo reference dye testing and avidity analysis, results take around 10 working days.