Saccharose-stabilized intravenous immune globulin as a cause of false-positive Aspergillus galactomannan assay in patients
Abstract number: P1759
Bougnoux M.E., Coignard H., Alanio A., Lanternier F., Charlier C., Suarez F., Catherinot E., Frange P., Debré M., Clement R., Ben Soltana M., Lecuit M., Bourget P., Lortholary O.
Objective: The detection of galactomannan (galactofuran) antigen (GMA) in serum by the Platelia®Aspergillus kit is extensively used for diagnosis of invasive aspergillosis (IA). However, the GMA assay yields a number of false positive results due to cross reactivity. Cross reactivity has already been described with some antibiotics or parenteral nutrition preparations. We observed a recent increase in the frequency of positive tests in patients receiving intravenous immune globulin (IVIG), with no evidence of IA at the time of sampling or during follow up. In this study, we prospectively investigated whether IVIG administration could induce false positive GMA test in 15 patients.
Methods: The sera from 9 adult patients who received saccharose-containing IVIG products (Sa-IVIG) and of 6 pts who received maltose-containing IVIG products (Ma-IVIG) were assayed for the presence of GMA. We also tested for GM (i) batches of IVIG solutions given to each of these patients, (ii) samples of 5 other commercially available IVIG (4 non-sugar- and 1 glucose-containing products), and (iii) each sugar alone at the concentration used to stabilize the IVIG preparations.
Results: GM was detected in sera from 6/9 patients treated by Sa-IVIG (index: 0.72), while all sera from patients receiving Ma-IVIG were negative. All Sa-IVIG batches tested yielded positive results (index: 27) while the other IGIV solutions were all negative. All saccharose solutions were positive (index: 23) while glucose and maltose solutions were negative.
Conclusions: These results demonstrated a strong cross reactivity between the Platelia® kit and Sa-IVIG. These false positive results could be due, in part, to a cross reactivity with saccharose which has a biochemical structure closely related to that of galactofuran which is detected by the assay. Clinicians should be aware of this problem which might lead to inappropriate suspicion of IA.
|Session name:||Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases|
|Location:||Vienna, Austria, 10 - 13 April 2010|
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