[Repeating the Platelia™ Aspergillus test in samples positive for serum galactomannan: Is it necessary?]

Abstract

Background: The manufacturers of the Platelia™ Aspergillus test recommend retesting every sample with a positive result to galactomannan detection.

Aims: To evaluate the repeated results of the Platelia™ Aspergillus test on initially positive samples, and their association with clinical and microbiological studies.

Methods: A total of 150 positive sera belonging to 92 patients were studied. More than one positive sample was obtained from 31 (33.6%) patients. Nine patients were diagnosed with probable invasive aspergillosis and two with proven Fusarium oxysporum and Scedosporium prolificans invasive fungal infection, respectively.

Results: Only 35 out of 150 (23.3%) sera remained positive upon test repetition. The average OD-index difference between the initially positive and subsequently negative samples was 0.76. Sera from 3 patients out of 9 diagnosed with probable invasive aspergillosis yielded negative results after repetition.

Conclusions: Our study shows poor reproducibility of the positive samples for the Platelia™ Aspergillus test. These results reinforce the need to evaluate a second sample and to consider simultaneously repeating the first positive serum to enhance the diagnosis of invasive fungal infection.

Keywords: Galactomanano; Galactomannan; Infección fúngica invasiva; Invasive fungal infection; Muestras positivas; Positive samples.