False-positive Aspergillus galactomannan immunoassays associated with intravenous human immunoglobulin administration.
OBJECTIVES
Evidence of false-positive galactomannan enzyme immunoassay (GM-EIA) results associated with intravenous immunoglobulin (IVIG) administration is scarce. Here, we aimed to determine the false-positive rate of GM-EIA after IVIG administration and to identify the related factors.


METHODS
Standard GM-EIA was performed using diluted and pure human IVIG samples with and without heat treatment. We also included adult patients who had at least one GM-EIA result within 1 week of IVIG administration for analysis. Those who had prior invasive aspergillosis within 1 year before IVIG therapy were excluded. The clinical characteristics and galactomannan index (GMI) kinetics between patients with false-positive and true-positive GMI were compared.


RESULTS
All diluted and pure IVIG samples tested positive for GM. Heat treatment resulted in the considerable elevation of GMI. Of 48 patients with positive GM-EIA results within 1 week of IVIG administration, 22 (45.8%) were considered to have false-positive antigenaemia (false-positive group, FPG). After the completion of IVIG administration, a decline in GMI was observed in all FPG patients but in only 18 out of 26 patients (69.2%) with true-positive results (true-positive group, TPG). By 7, 14, and 18 days of IVIG administration, GMI reverted to negative values in 7/15 (46.7%), 18/20 (90%) and 22/22 (100%) FPG patients, respectively, and 6/24 (25%), 14/24 (58.3%), and 16/26 (61.5%) of TPG patients, respectively. The TPG was more likely to have two or more consecutively positive GMIs after IVIG administration than the FPG (adjusted odds ratio, 9.01; 95% confidence interval, 1.99-40.9).


CONCLUSIONS
IVIG treatment may produce false-positive GM-EIA results. A positive GMI among patients receiving human IVIG should be interpreted with caution.
['Liu|W-D|WD|', 'Lin|S-W|SW|', 'Shih|M-C|MC|', 'Su|C-L|CL|', 'Wang|Y-W|YW|', 'Lin|S-C|SC|', 'Lee|Y-F|YF|', 'Huang|H-H|HH|', 'Chou|W-C|WC|', 'Wu|U-I|UI|', 'Chen|Y-C|YC|', 'Chang|S-C|SC|']
D000328:Adult D003430:Cross-Sectional Studies D005189:False Positive Reactions D005260:Female D005690:Galactose D006358:Hot Temperature D006801:Humans D007124:Immunoenzyme Techniques D016756:Immunoglobulins, Intravenous D008297:Male D008351:Mannans
False-positive Aspergillus Galactomannan Human immunoglobulin IVIG