title: Immunoglobulin M indirect-fluorescent antibody test for the diagnosis of acute toxoplasmosis during pregnancy in the avidity era: A 14-year experience at the Tuscany Reference Center for Infectious Diseases in Pregnancy, Florence, Italy.
abstract: OBJECTIVE
  The aim of this study was to evaluate immunoglobulin M indirect-fluorescent antibody test (IgM IFAT) for the diagnosis of acute or chronic Toxoplasma infection in pregnancy.
  
  
  METHODS
  Pregnant women with suspected acute toxoplasmosis referred to the Tuscany Reference Center for Infectious Diseases in Pregnancy during the period 1998-2012 were retrospectively enrolled. All women were tested with a panel of serological tests, including enzyme-linked immunosorbent assay for IgG avidity and IgM IFAT. On the basis of anamnestic, clinical, and serological criteria, pregnant women were classified into three groups: recently infected (RI), latently infected (LI), and doubtful latently infected (DLI). Patients classified as DLI were excluded from the analysis. The association between IgM IFAT (positive or negative) and the diagnosis of infection (acute or chronic) was assessed. Positive predictive value and negative predictive value of the IgM IFAT were calculated.
  
  
  RESULTS
  A total of 810 pregnant women were enrolled in the study: 302 in the RI group and 508 in the LI group. Fifty-two women classified as DLI were excluded. IgM IFAT was positive in 172 out of 302 (56.9%) pregnant women in the RI group and in 29 out of 508 (5.7%) in the LI group. The positive predictive value and negative predictive value of IgM IFAT in predicting RI was 85.6% and 78.6%, respectively.
  
  
  CONCLUSIONS
  IgM IFAT has reasonable sensitivity and specificity in diagnosing recent infection and, mostly in case of borderline avidity test, could be considered as a further aid for an accurate diagnosis of acute toxoplasmosis in pregnancy.
authors.affiliation: Infectious and Tropical Diseases Unit, Careggi University Hospital, Florence, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Trotta
authors.affiliation: Infectious and Tropical Diseases Unit, Careggi University Hospital, Florence, Italy.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Borchi
authors.affiliation: Infectious and Tropical Diseases Unit, Careggi University Hospital, Florence, Italy.|Infectious Diseases Clinic, Department of Experimental & Clinical Medicine, University of Florence, Florence, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Zammarchi
authors.affiliation: Infectious and Tropical Diseases Unit, Careggi University Hospital, Florence, Italy.
authors.forename: Gaetana
authors.initials: G
authors.lastname: Sterrantino
authors.affiliation: Infectious Diseases Clinic, Department of Experimental & Clinical Medicine, University of Florence, Florence, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Brogi
authors.affiliation: Infectious Diseases Clinic, Department of Experimental & Clinical Medicine, University of Florence, Florence, Italy.
authors.forename: Seble Tekle
authors.initials: ST
authors.lastname: Kiros
authors.affiliation: Department of Health Sciences, University of Florence, Florence, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Lorini
authors.affiliation: Health Services Research Unit, Department of Experimental & Clinical Medicine, University of Florence, Florence, Italy.
authors.forename: Guglielmo
authors.initials: G
authors.lastname: Bonaccorsi
authors.affiliation: Microbiology & Virology Unit, Careggi University Hospital, Florence, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Colao
authors.affiliation: Infectious and Tropical Diseases Unit, Careggi University Hospital, Florence, Italy.|Infectious Diseases Clinic, Department of Experimental & Clinical Medicine, University of Florence, Florence, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Bartoloni
mesh_terms: D000913:Antibodies, Protozoan / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005455:Fluorescent Antibody Technique; D005865:Gestational Age; D006801:Humans; D007075:Immunoglobulin M / Q000032:analysis* / Q000097:blood; D007558:Italy; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014123:Toxoplasmosis / Q000175:diagnosis* / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan; D007075:Immunoglobulin M
keywords: Toxoplasma gondii; congenital; diagnosis; pregnancy; serology; toxoplasmosis