Biomedical subjects

Kari Hauge Olsen

Publications and source records attributed to Kari Hauge Olsen.

3 recordsLinked to original sources

PubMed2005

Human heterophilic antibodies display specificity for murine IgG subclasses.

OBJECTIVES: The study investigated heterophilic antibodies: the human immunoglobulin classes involved and their specificity for different murine IgG subclasses. DESIGN AND METHODS: Using immunofluorometric assays for human IgA, IgM and IgG binding murine IgG1, we analyzed 173 samples displaying positive interference and 97 negative control samples from a previous study. We also set up assays for heterophilic antibody interference using Mabs from different murine IgG subclasses. Three Mabs each of murine IgG1, IgG2a and IgG2b subclasses, one murine IgG3 Mab and one rat Mab were used. RESULTS: Elevated levels of human murine IgG1-binding immunoglobulins of IgM class only were found in 40% of interference-positive samples, human IgG only in 1.7%, and human IgA only in 2.3% of the samples. Both elevated human IgG and IgM classes were found in 3.5% of the samples, IgA and IgM in 4.0%, and finally, all three immunoglobulin classes in 1.7% of the samples. Eighty percent of interference positive samples showed heterophilic assay interference for at least one murine IgG1 Mab, 35% for IgG2a, 66% for IgG2b, 52% for IgG3a and 17% for the rat Mab. CONCLUSIONS: Heterophilic antibody interference is mainly caused by IgM class human antibodies with a marked murine IgG subclass specificity. Combining assay antibodies from different murine IgG subclasses may reduce interference in immunoassays.

Animals↗

PubMed2004

Testing and validating a homogeneous immunometric assay for interference.

We analyzed 95 sera, demonstrating interference in a previous study, with the Kryptor homogeneous time-resolved fluorescence resonance energy transfer carcinoembryonic antigen (CEA) immunoassay (Brahms AG, Berlin, Germany). Only one serum differed, i.e., 6.0 microg/l for Kryptor vs. 13.3 microg/l for a microtiter plate in-house immunofluorometric assay (IFMA), using both aggregated mouse immunoglobulins as blocker and capture monoclonal antibody (Mab) F(ab')2-fragments to reduce interference. Sera were further analyzed with experimental IFMAs with intact capture Mabs and without blocker. The Kryptor-CEA assay Mab GFR44 (capture) had elevated results in 71% of sera with the Kryptor Mab G15 (tracer) or in 81% with our tracer Mab. G15 (capture) had 65% elevated results with GFR44 (tracer) or 99% with our tracer Mab. The latter was reduced from 99% to 62% by adding Kryptor blocker to the buffer or to 30% by adding our blocker. Finally, combining both assay Mabs and assay buffer from Kryptor still gave interference in 16% of sera. Kryptor-CEA assay results thus agreed with our in-house CEA assay results, showing no interference. As the Kryptor-CEA assay antibodies were sensitive to interference and the Kryptor-CEA assay buffer did not reduce interference as efficiently as our in-house assay buffer, the Kryptor-CEA assay format was crucial for the absence of interference.

Animals↗

PubMed2002

Immunometric assay interference: incidence and prevention.

BACKGROUND: The primary aim of the study was to reduce interference in an in-house two-site, two-step immunometric assay. METHODS: In the running laboratory routine, 11 261 samples were tested with a carcinoembryonic antigen (CEA) assay with bovine immunoglobulin but no murine immunoglobulins in the buffer, in parallel to our routine CEA assay, using 15 mg/L heat-treated nonspecific murine immunoglobulin (MAK33) in the buffer and with the Fc fragments removed from the capture antibody. RESULTS: The frequency of interference was estimated to be 4.0% (95% confidence interval, 3.3-4.7%). The addition of 15 mg/L native MAK33 had little effect (frequency, 3.9%; 95% confidence interval, 3.2-4.6%), whereas adding 15 mg/L heat-treated MAK33 reduced interference to 0.86% (0.61-1.12%), and adding 50 mg/L reduced it further to 0.06% (0-0.13%). Removing the Fc fragments by itself reduced interference to 0.10% (0.02-0.19%). There were no statistically significant differences for age (P <0.23) or gender (P <0.40) between patients with interference (n = 210) and a randomly selected interference-negative control group (n = 186). Interference was not constant in patients: 15 of 25 individuals positive for interference and with four or more samples screened for interference had an interference-negative sample either before or after the peak of interference. CONCLUSIONS: In a two-site, two-step immunometric assay using mouse monoclonal antibodies, use of heat-treated nonspecific murine immunoglobulin in the buffer or removal of the Fc fragment from the capture antibody could improve performance.

Animals↗