IgG avidity assay

A tool for excluding acute toxoplasmosis in prolonged IgM titer sera from pregnant women

Emelia Osman, Rahana Abd Rahman, A. Mohamad Firdaus, H. S. Cheng, M. S. Nursyairah, A. S. Fatinah, Azmawati Mohammed Nawi, N. A M Siti, M. Y. Aisah

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

An accurate diagnosis for toxoplasmosis is crucial for pregnant women as this infection may lead to severe sequelae in the fetus. The value of IgG avidity assay as a tool to determine acute and chronic toxoplasmosis during pregnancy was evaluated in Universiti Kebangsaan Malaysia Medical Centre (UKMMC). In this study, 281 serum samples from 281 pregnant women in various trimesters were collected. These samples were assayed using specific anti-Toxoplasma IgM and IgG antibodies, followed by IgG avidity test. The overall seroprevalence of toxoplasmosis in pregnant women was 35.2% (33.5% for anti-Toxoplasma IgG and 1.8% for both anti-Toxoplasma IgG and IgM antibodies). Of 5 (1.8%) serum samples positive for IgM ELISA, 4 had high-avidity antibodies, suggesting past infection and one sample with borderline avidity index. Two samples with low avidity were from IgM negative serum samples. The IgG avidity assay exhibited an excellent specificity of 97.6% and a negative predictive value (NPV) of 95.6%. The study also demonstrated no significant correlation between avidity indexes of the sera with IgG (r=0.12, p=0.24) and IgM (r=-0.00, p=0.98), suggesting the complementary needs of the two tests for a better diagnosis outcome. These findings highlight the usefulness of IgG avidity assay in excluding a recently acquired toxoplasmosis infection in IgM-positive serum sample.

Original languageEnglish
Pages (from-to)633-640
Number of pages8
JournalTropical Biomedicine
Volume31
Issue number4
Publication statusPublished - 2014

Fingerprint

Toxoplasmosis
Immunoglobulin M
Pregnant Women
Immunoglobulin G
Toxoplasma
Serum
Infection
Antibody Affinity
Antibodies
Malaysia
Seroepidemiologic Studies
Fetus
Enzyme-Linked Immunosorbent Assay
Pregnancy
anti-IgG
anti-IgM

ASJC Scopus subject areas

  • Infectious Diseases
  • Parasitology

Cite this

Osman, E., Abd Rahman, R., Mohamad Firdaus, A., Cheng, H. S., Nursyairah, M. S., Fatinah, A. S., ... Aisah, M. Y. (2014). IgG avidity assay: A tool for excluding acute toxoplasmosis in prolonged IgM titer sera from pregnant women. Tropical Biomedicine, 31(4), 633-640.

IgG avidity assay : A tool for excluding acute toxoplasmosis in prolonged IgM titer sera from pregnant women. / Osman, Emelia; Abd Rahman, Rahana; Mohamad Firdaus, A.; Cheng, H. S.; Nursyairah, M. S.; Fatinah, A. S.; Mohammed Nawi, Azmawati; Siti, N. A M; Aisah, M. Y.

In: Tropical Biomedicine, Vol. 31, No. 4, 2014, p. 633-640.

Research output: Contribution to journalArticle

Osman, E, Abd Rahman, R, Mohamad Firdaus, A, Cheng, HS, Nursyairah, MS, Fatinah, AS, Mohammed Nawi, A, Siti, NAM & Aisah, MY 2014, 'IgG avidity assay: A tool for excluding acute toxoplasmosis in prolonged IgM titer sera from pregnant women', Tropical Biomedicine, vol. 31, no. 4, pp. 633-640.
Osman, Emelia ; Abd Rahman, Rahana ; Mohamad Firdaus, A. ; Cheng, H. S. ; Nursyairah, M. S. ; Fatinah, A. S. ; Mohammed Nawi, Azmawati ; Siti, N. A M ; Aisah, M. Y. / IgG avidity assay : A tool for excluding acute toxoplasmosis in prolonged IgM titer sera from pregnant women. In: Tropical Biomedicine. 2014 ; Vol. 31, No. 4. pp. 633-640.
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