A Novel Point-of-Care Rapid Diagnostic Test for Screening Individuals for Antibody Deficiencies

Abstract

Purpose No rapid diagnostic test exists to screen individuals for primary antibody deficiencies (PAD) at or near the point of care. In settings at risk for polio where live oral polio vaccine is utilized, undiagnosed PAD patients and cases with delayed diagnosis constitute a potential reservoir for neurovirulent polioviruses, undermining polio eradication. This research aimed to develop a rapid screening test suited for use in resource-limited settings to identify individuals with low immunoglobulin G (IgG) levels, enabling early diagnosis and appropriate treatment. Methods Three prototype tests distinguishing low and normal IgG levels were evaluated with a blinded panel of serum/plasma specimens from 32 healthy controls and 86 primary immunodeficiency-confirmed patients with agammaglobulinemia, common variable immunodeficiency, and hyper-IgM syndrome, including 57 not receiving IgG therapy. Prototype tests were compared to laboratory reference and clinical case definition. Results The leading prototype correctly identified 32 of 32 healthy controls. Among primary antibody deficiency patients not receiving IgG treatment, 17 of 19 agammaglobulinemia, 7 of 24 common variable immunodeficiency, and 5 of 14 hyper-IgM were correctly identified by the prototype, with 67% agreement with the reference assay. Conclusion The Rapid IgG Screen (RIgGS) test can differentiate between low IgG levels associated with agammaglobulinemia and normal IgG antibody levels. Differentiating CVID and hyper IgM was challenging due to the wide range in IgG levels and influence of high IgM. This test can facilitate the identification of patients with primary antibody deficiencies and support polio surveillance initiatives.

Point of care detection of SARS-CoV-2 antibodies and neutralisation capacity—lateral flow immunoassay evaluation compared to commercial assay to inform potential role in therapeutic and surveillance practices

“…Success in the use of POC tests for disease screening, particularly in low-resource healthcare settings, has been demonstrated for many non-coronavirus conditions, such as HIV ( 42 ), malaria ( 43 ), sickle cell disease ( 44 ), and chlamydia ( 45 ). This test modality may benefit patients in healthcare settings where laboratory facilities, result turnaround, and follow-up options are limited ( 46 ). A test modality that is easy to distribute, perform, and interpret is also beneficial for future pandemic preparedness.…”

Navigating diagnostic options for inborn errors of immunity in children: a case-based illustration

“…These assays are readily available in most clinical settings in developed nations. A recently developed rapid point-of-care test may prove useful in resource-poor settings or in settings in which rapid diagnosis would potentially change management [31]. IgG subclasses may be measured, but deficiencies in IgG subclasses are most relevant when they occur in conjunction with other humoral defects such as IgA deficiency or antipolysaccharide antibody deficiency [30,32].…”