An IgM lambda antibody to Escherichia coli produces false-positive results in multiple immunometric assays.
Publication/Presentation Date
8-1-2000
Abstract
BACKGROUND: Interferences in immunometric assays as a result of human anti-immunoglobulin antibodies frequently have been described in the literature. The etiology of these interfering antibodies is usually not known but has been associated with rheumatoid factors in some assays. It is known that microorganisms in experimental settings can induce anti-immunoglobulin antibodies.
METHODS: Following Escherichia coli septicemia, a 56-year-old male patient had increased immunoassay results for cardiac troponin I, thyrotropin, human chorionic gonadotropin, alpha-fetoprotein, and CA-125 that were consistent with myocardial infarction, hyperthyroidism, and pregnancy, and suggestive of an occult neoplasm such as hepatic or ovarian cancer. None of these diagnoses were consistent with the rest of his medical exam. In addition, the patient had a restricted IgM lambda paraprotein by immunofixation. Plasma from the patient was incubated with Sepharose-conjugated protein A, irrelevant murine monoclonal antibodies, and formalin-killed E. coli organisms from his infection to determine whether these immunoassay values were falsely increased.
RESULTS: Incubation of the patient's plasma with irrelevant murine monoclonal antibodies or the E. coli organism produced normal immunoassay values and removed the IgM lambda paraprotein.
CONCLUSIONS: The patient produced a very restricted IgM lambda antibody response to the E. coli infection that had anti-immunoglobulin activity and caused falsely increased values in numerous immunometric assays. Microorganism-induced anti-immunoglobulin antibodies are discussed in the context of this patient.
Volume
46
Issue
8 Pt 1
First Page
1157
Last Page
1161
ISSN
0009-9147
Published In/Presented At
Covinsky, M., Laterza, O., Pfeifer, J. D., Farkas-Szallasi, T., & Scott, M. G. (2000). An IgM lambda antibody to Escherichia coli produces false-positive results in multiple immunometric assays. Clinical chemistry, 46(8 Pt 1), 1157–1161.
Disciplines
Medicine and Health Sciences
PubMedID
10926897
Department(s)
Department of Pathology and Laboratory Medicine
Document Type
Article