In-vitro detection of mannan and galactomannan in components of total parenteral nutrition (TPN).

Abstract

Detection of Candida mannan and Aspergillus galactomannan in serum with the Platelia enzyme immunoassay is applied for diagnosing invasive fungal infections. High risk patients for invasive fungal infections are often receiving parenteral nutrition. It is important to know whether false-positive Platelia test results occur during total parenteral nutrition. Studies to false-positivity in intravenous feeding solutions lack so that we start an in-vitro investigation. We used two different enzyme immunoassays to test the feeding solutions. We tested infusions (n = 19) which are applied for the production of individual parenteral nutrition in the University Hospital Carl Gustav Carus Dresden. We used the Platelia Aspergillus EIA to analyse the Aspergillus antigen galactomannan in the solutions. In addition, the Platelia Candida Ag plus was used to determine the concentration of the Candida antigen mannan. In summary, four solutions (21%) showed measurable concentrations of the Candida mannan. They were considered positive with a concentration > 0.125 ng/ ml mannan (Tracitrans infant, calcium gluconate solution) and borderline with a concentration between 0.0625 and 0.125 ng/ml mannan (Tracitrans plus, SMOFlipid). None of the analysed infusions contained the Aspergillus galactomannan. In conclusion, further investigations on the topic are necessary to determine their in-vivo impact. A positive Platelia test result can simulate the presence of invasive fungal infections. As a consequence the patient may be treated with expensive, systemic antimycotics with a high risk of adverse events. Therefore a definite diagnosis is important.