Positive Predictive Value of Myelin Oligodendrocyte Glycoprotein Autoantibody Testing.
JAMA Neurol
; 78(6): 741-746, 2021 06 01.
Article
em En
| MEDLINE
| ID: mdl-33900394
ABSTRACT
Importance Myelin oligodendrocyte glycoprotein-IgG1-associated disorder (MOGAD) is a distinct central nervous system-demyelinating disease. Positive results on MOG-IgG1 testing by live cell-based assays can confirm a MOGAD diagnosis, but false-positive results may occur. Objective:
To determine the positive predictive value (PPV) of MOG-IgG1 testing in a tertiary referral center. Design, Setting, andParticipants:
This diagnostic study was conducted over 2 years, from January 1, 2018, through December 31, 2019. Patients in the Mayo Clinic who were consecutively tested for MOG-IgG1 by live cell-based flow cytometry during their diagnostic workup were included. Patients without research authorization were excluded. Main Outcomes andMeasures:
Medical records of patients who were tested were initially reviewed by 2 investigators blinded to MOG-IgG1 serostatus, and pretest probability was classified as high or low (suggestive of MOGAD or not). Testing of MOG-IgG1 used a live-cell fluorescence-activated cell-sorting assay; an IgG binding index value of 2.5 or more with an end titer of 120 or more was considered positive. Cases positive for MOG-IgG1 were independently designated by 2 neurologists as true-positive or false-positive results at last follow-up, based on current international recommendations on diagnosis or identification of alternative diagnoses; consensus was reached for cases in which disagreement existed.Results:
A total of 1617 patients were tested, and 357 were excluded. Among 1260 included patients tested over 2 years, the median (range) age at testing was 46 (0-98) years, and 792 patients were female (62.9%). A total of 92 of 1260 (7.3%) were positive for MOG-IgG1. Twenty-six results (28%) were designated as false positive by the 2 raters, with an overall agreement on 91 of 92 cases (99%) for true and false positivity. Alternative diagnoses included multiple sclerosis (n = 11), infarction (n = 3), B12 deficiency (n = 2), neoplasia (n = 2), genetically confirmed adrenomyeloneuropathy (n = 1), and other conditions (n = 7). The overall PPV (number of true-positive results/total positive results) was 72% (95% CI, 62%-80%) and titer dependent (PPVs 11000, 100%; 1100, 82%; 120-40, 51%). The median titer was higher with true-positive results (1100 [range, 120-110000]) than false-positive results (140 [range, 120-1100]; P < .001). The PPV was higher for children (94% [95% CI, 72%-99%]) vs adults (67% [95% CI, 56%-77%]) and patients with high pretest probability (85% [95% CI, 76%-92%]) vs low pretest probability (12% [95% CI, 3%-34%]). The specificity of MOG-IgG1 testing was 97.8%. Conclusions and Relevance This study confirms MOG-IgG1 as a highly specific biomarker for MOGAD, but when using a cutoff of 120, it has a low PPV of 72%. Caution is advised in the interpretation of low titers among patients with atypical phenotypes, because ordering MOG-IgG1 in low pretest probability situations will increase the proportion of false-positive results.
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Autoanticorpos
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Imunoglobulina G
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Doenças Desmielinizantes
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Glicoproteína Mielina-Oligodendrócito
Tipo de estudo:
Diagnostic_studies
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Guideline
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Prognostic_studies
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Risk_factors_studies
Limite:
Adolescent
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Adult
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Aged
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Aged80
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Child
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Child, preschool
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Female
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Humans
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Infant
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Male
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article