3 mL plain blood Paired acute and convalescent sera (3 – 6 weeks after onset of fever) should be sent. Acute phase sera are tested alone; a convalescent specimen is requested and when received will be run together with the acute phase sera. Ideally, paired acute and convalescent sera should be sent for both IgM and IgG. (Please see Toxoplasma Antibody, IgM.)
Titres <1:16. No previous infection.
A four-fold rise in titre, between acute and convalescent specimens, is necessary for laboratory confirmation of acute infection.
Titres 1:16 – 1:1024. Titres of single specimens or unchanged titres in paired specimens cannot give information on the timing of past infection. IgG antibody levels generally peak 6-8 weeks after infection and remain detectable thereafter.
Titres >1:1024. Titres are very high, possible recent infection if accompanied by supporting clinical presentations. Acute infections can only be confirmed by paired testing with convalescent specimens.
Range 1 – 4 days
Monday – Friday