2031. False Positive Serologic Results attributable to IVIG therapy
Session: Poster Abstract Session: Diagnostics: Biomarkers and Novel Approaches
Saturday, October 6, 2018
Room: S Poster Hall
Background: Intravenous immunoglobulin (IVIG) is used to treat an increasing number of conditions including hematologic, rheumatologic and immunodeficiency diseases. The immunomodulatory effects can be life-saving, however recent administration can complicate diagnostics when patients later present with symptoms necessitating serologic testing. We evaluated the serologic profile of IVIG for commonly ordered infectious diseases serologies.

Methods: Patients were enrolled if they received and were naïve to IVIG therapy. Blood was drawn prior to IVIG and 72-96 hours post-infusion. All samples were tested for: Bartonella, Coccidioides, Brucella, Histoplasma, Coxiella, West Nile, St. Louis, California, Eastern, and Western Encephalitis, Lyme, Dengue, HSV 1 and 2, Chikungunya, cytomegalovirus, varicella zoster, Epstein-Barr and Toxoplasma by standard methodologies (ARUP, Salt Lake City, UT). Pre- and post-infusion antibody concentrations were evaluated to determine the potential false-positive rate of serologic testing.

Results: Seven patients received IVIG (renal transplant rejection, 2 patients; Guillain-Barre syndrome, 3 pts; bone marrow transplant, 2 pts). Six of seven patients receiving IVIG had at least one evaluated serology become positive 72 hours after IVIG infusion. Antibodies for CMV, HSV-2, and EBV early antigen D turned positive in 3 patients. Antibodies for WNV, Coccidioides IgG, and Histoplasma yeast IgG became positive in 2 patients. Lastly, antibodies for HSV-1 and 2, and EBV nuclear antigen each turned positive in 1 patient.

Patients received between 20-112.5 grams. Of the 3 patients who received more than 100g of IVIG, 2 had at least 4 serologies turn positive. Of the patients who received less than 100g (20 – 50g), none had more than 3 turn positive (p <0.05). One patient had 3 serologies turn negative (Coccidioides, HSV 2, and EBV Early D) after infusion of 36.5g of IVIG, with none turning positive.

Conclusion: Use of IVIG has increased significantly over the past decade, however the potential pitfalls in serologic diagnostics associated with receipt of IVIG have not been studied systematically and is likely a confounder in serologic diagnostics causing both false-positive and false-negative results. We found a number of screening and diagnostic serologies can be artificially altered after infusion of IVIG.

Kimberly E. Hanson, MD, MHS, University of Utah School of Medicine, Salt Lake City, UT, Nielsen Gabriel, BA, UC-Davis Medical Center, Sacramento, CA, Ian Mchardy, PhD, Medical Microbiology and Immunology, UC Davis, Davis, CA, Wesley Hoffmann, Pharm.D., Department of Pharmacy, University of California Davis Medical Center, Sacramento, CA, Stuart H. Cohen, MD, FIDSA, FSHEA, FACP, Internal Medicine, University of California, Davis Medical Center, Sacramento, CA, Ryan Welch, BS, R&D Immunology, Associated Regional and University Pathologists (ARUP) Institute for Clinical and Experimental Pathology, Salt Lake City, UT, Marc Roger Couturier, Ph.D., D(ABMM), Pathology, University of Utah, Salt Lake City, UT and George R. Thompson, MD, Medical Microbiology and Immunology, University of California, Davis, Davis, CA

Disclosures:

K. E. Hanson, None

N. Gabriel, None

I. Mchardy, None

W. Hoffmann, None

S. H. Cohen, None

R. Welch, None

M. R. Couturier, None

G. R. Thompson, None

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