Value of antigen detection in the diagnosis of invasive aspergillosis
Abstract number: 1134_03_256
Grapsa A., Kartali S., Kantzanou M., Margaritis D., Karavassiliadou S., Panopoulou M., Archondidou E., Bourikas G.
Invasiveaspergillosis (IA) has been a significant cause of life-threatening opportunistic infections in immunosuppressed hosts. Early diagnosis is important to achieve the best outcome for these patients; however, definite proof often is difficult to obtain due to counterindicated invasive procedures. Serum galactomannan detection is considered to be a useful test for early diagnosis and follow up of invasive aspergillosis.
This study evaluated the specificity and sensitivity of the detection of galactomannan(GM) for the diagnostic of IA in 98 adult patients hospitalized in our Hematology unit. Patients were considered to have confirmed or probable invasiveaspergillosis, based on clinical and radiological data. Serial screening of Aspergillus GM circulating antigen was evaluated using a double sandwich ELISA assay (PlateliaAspergillus, BioRad, France) on 760 sera. Test positivity was defined in accordance with the manufacturer's recommendations.
Among the patients studied, 10 (10.2%) presented with confirmed IA (n = 8 patients) or probable IA (n = 2 patients). Seven patients (7.1%) having a positive result (OD index >1.5) in two consecutive PlateliaAspergillus tests were considered galactomannan positive cases. No antigens were detected in the sera from one patient with confirmed IA. Latex agglutination assay of galactomannan was positive in both patients with probable IA. In patients without IA, 9 of 88 had positive antigenemia. Sensitivity (70%), specificity (89%), were comparable to those of larger series. Circulating antigens were not detected in the control group, composed of healthy adults. The gradual rise in the antigen titer in consecutive samples is a very strong indication that an infection is present and should be taken into account when interpreting the results.
The detection of the circulating Aspergillusgalactomannan antigen by a sandwich enzyme-linked immunosorbent assay (ELISA) is one of the most promising method to diagnose IA in at-risk patients. The presence of antigen has a good diagnostic value mainly when there is an increase in the titer on two consecutive sera samples. A repeated negative result is a strong argument against the diagnosis of IA.
|Session name:||XXIst ISTH Congress|
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