title: Long-term sera storage does not significantly modify the interpretation of toxoplasmosis serologies.
abstract: Serological investigation of Toxoplasma gondii can answer many questions about toxoplasmosis in human pathology. Along these lines, studies on serum storage in biobanks need to be performed especially in terms of determining the impact of storage on relevance of sera analysis after freezing. This study assessed the impact of long-term sera storage on the stability of anti-Toxoplasma immunoglobulins.
  
  
  
  The stability of anti-Toxoplasma IgG and IgM was studied in 244 and 242 sera respectively, stored at -20°C from one month to ten years. ELISA-immunoassay (Vidas®, bioMérieux) was used for initial and post-storage analyses. Linear models for repeated measures and subgroup analyses were performed to assess the effect of storage duration and sample characteristics on immunoglobulins stability.
  
  
  
  Until ten years, the variability attributed to storage (maximum 8.07% for IgG, 13.17% for IgM) was below the variations inherent to the serological technique and allowed by quality assurance systems (15%). Subgroup analysis reported no variation attributed to sera storage. Serological interpretation was modified for 3 sera (1.2%) tested for IgM, all stored more than seven years.
  
  
  
  Anti-Toxoplasma immunoglobulins can reliably be measured for at least up to six years of storage with no modification of interpretation of toxoplasmosis serologies.
authors.affiliation: Laboratoire de Parasitologie-Mycologie, Institut de Biologie et Pathologie, CHU Grenoble Alpes, France; Institute for Advanced Biosciences (IAB), Team Host-Pathogen Interactions and Immunity to Infection, INSERM U1209 - CNRS UMR5309, Université Grenoble Alpes, 38700 Grenoble, France.
authors.forename: C
authors.initials: C
authors.lastname: Dard
authors.affiliation: Laboratoire de Parasitologie-Mycologie, Institut de Biologie et Pathologie, CHU Grenoble Alpes, France; UMR 1137-IAME Team 5-DeSCID, Inserm/Paris Diderot, Université Sorbonne Paris Cité, Paris, France.
authors.forename: S
authors.initials: S
authors.lastname: Bailly
authors.affiliation: Laboratoire de Parasitologie-Mycologie, Institut de Biologie et Pathologie, CHU Grenoble Alpes, France.
authors.forename: T
authors.initials: T
authors.lastname: Drouet
authors.affiliation: Laboratoire de Parasitologie-Mycologie, Institut de Biologie et Pathologie, CHU Grenoble Alpes, France.
authors.forename: H
authors.initials: H
authors.lastname: Fricker-Hidalgo
authors.affiliation: Laboratoire de Parasitologie-Mycologie, Institut de Biologie et Pathologie, CHU Grenoble Alpes, France; Institute for Advanced Biosciences (IAB), Team Host-Pathogen Interactions and Immunity to Infection, INSERM U1209 - CNRS UMR5309, Université Grenoble Alpes, 38700 Grenoble, France.
authors.forename: M P
authors.initials: MP
authors.lastname: Brenier-Pinchart
authors.affiliation: Laboratoire de Parasitologie-Mycologie, Institut de Biologie et Pathologie, CHU Grenoble Alpes, France; Institute for Advanced Biosciences (IAB), Team Host-Pathogen Interactions and Immunity to Infection, INSERM U1209 - CNRS UMR5309, Université Grenoble Alpes, 38700 Grenoble, France. Electronic address: hpelloux@chu-grenoble.fr.
authors.forename: H
authors.initials: H
authors.lastname: Pelloux
mesh_terms: D000913:Antibodies, Protozoan / Q000097:blood* / Q000276:immunology; D001771:Blood Banks; D003080:Cold Temperature; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D011786:Quality Control; D012698:Serologic Tests; D013997:Time Factors; D014122:Toxoplasma / Q000276:immunology*; D014123:Toxoplasmosis / Q000097:blood / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan; D007074:Immunoglobulin G; D007075:Immunoglobulin M
keywords: Biobank; Freezing; Parasitology; Serum; Stability; Storage; Toxoplasma gondii; Toxoplasmosis