A twelve-month retrospective audit of reactive Toxoplasma gondii serology in pregnant women in Ireland

Abstract number: P2089

Objectives: Primary maternal infection with Toxoplasma gondii may result in transplacental transmission of infection to the fetus. Prompt and accurate recognition of primary maternal toxoplasma infection enables initiation of effective anti-toxoplasma chemotherapy. Interpretation of Toxoplasma serology results can prove challenging. Patients may have detectable IgM levels to T. gondii which persist for months to years following primary infection and false positive IgM results are not uncommon. Referral to a reference laboratory for further confirmation of reactive T. gondii serology is recommended in pregnant women. This audit was carried out to determine the indication for performing T. gondii serology on women of childbearing age and to determine the frequency and significance of reactive serology results.

Methods: The results and clinical information of 2,497 samples tested for antibodies to T. gondii, received from females aged fourteen to fifty years of age from January 1st to December 31st 2007 were reviewed.

Results: Of 540 women of childbearing age with reactive T. gondii serology, 234 (43%) were pregnant or had been recently pregnant at the time of testing. Routine antenatal screening and investigation of intrauterine death were the testing indications for 82% of reactive T. gondii specimens.

There was no serological evidence of recent T. gondii infection in 218 (93%) of pregnant women with reactive T. gondii serology. Twelve pregnant women had a first positive IgM to T. gondii. High IgG avidity results were recorded in nine of ten IgM positive specimens, indicating that the T. gondii infection was not acquired in the preceding three months.

One sample had low IgG avidity, confirmed at the Toxoplasma Reference Unit (TRU) suggestive of a recently acquired T. gondii infection. The indication for performing T. gondii serology in that case was presence of fetal ventriculomegaly on ultrasound examination.

Conclusions: It was possible to confirm recent acquisition of primary T. gondii infection in only one of 234 pregnant women with reactive serology for T. gondii in 2007. The results of this audit suggest that testing for T. gondii as part of routine antenatal screening in the absence of a clinical indication should be reconsidered owing to the implications of detection of a positive IgM result for a pregnant woman.

Routine testing for T. gondii in the investigation of intrauterine death should also be reevaluated owing to the low yield of positive results.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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