False-positive results in premature infants with the Platelia® Aspergillus sandwich enzyme-linked immunosorbent assay

The sensitivity of a sandwich enzyme-linked immunosorbent assay (ELISA) for detecting Aspergillus galactomannan was tested using 783 serum samples obtained from 247 patients (1-15 sera per patient) with severe underlying diseases (haematological malignancies or intensive care unit stay). We selected 146 serum samples from 50 patients for retesting. Serum samples were frozen after routine testing at -18 degrees C until retesting. All patient charts were checked for signs of Aspergillus infection, such as pneumonia or sinusitis. Adult patients were divided into four groups: proven (5), probable (6), suspected (8) or unlikely (25) Aspergillus infection. The results of Platelia(R) ELISA were 100% in proven, 33% in probable and 50% in suspected Aspergillus infection. Patients with unlikely infection had no positive results with Platelia(R) ELISA. Group 5 consists of six paediatric patients with prolonged ICU stay and a birth weight of 400-1320 g. In five out of six infants we found positive results with Platelia(R) ELISA. All positive results in this group of patients are considered as false positive (83.3%).