title: Comparison of two real-time PCR assays for the detection of malaria parasites from hemolytic blood samples - Short communication.
abstract: We compared the performance of an in-house and a commercial malaria polymerase chain reaction (PCR) assay using freeze-thawed hemolytic blood samples. A total of 116 freeze-thawed ethylenediamine tetraacetic acid (EDTA) blood samples of patients with suspicion of malaria were analyzed by an in-house as well as by a commercially available real-time PCR. Concordant malaria negative PCR results were reported for 39 samples and malaria-positive PCR results for 67 samples. The in-house assay further detected one case of Plasmodium falciparum infection, which was negative in the commercial assay as well as five cases of P. falciparum malaria and three cases of Plasmodium vivax malaria, which showed sample inhibition in the commercial assay. The commercial malaria assay was positive in spite of a negative in-house PCR result in one case. In all concordant results, cycle threshold values of P. falciparum-positive samples were lower in the commercial PCR than in the in-house assay. Although Ct values of the commercial PCR kit suggest higher sensitivity in case of concordant results, it is prone to inhibition if it is applied to hemolytic freeze-thawed blood samples. The number of misidentifications was, however, identical for both real-time PCR assays.
authors.affiliation: Department of Tropical Medicine at the Bernhard Nocht Institute, German Armed Forces Hospital of Hamburg , Germany.
authors.forename: Ralf Matthias
authors.initials: RM
authors.lastname: Hagen
authors.affiliation: Department of Tropical Medicine at the Bernhard Nocht Institute, German Armed Forces Hospital of Hamburg , Germany.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Hinz
authors.affiliation: Bernhard Nocht Institute for Tropical Medicine Hamburg , Germany.
authors.forename: Egbert
authors.initials: E
authors.lastname: Tannich
authors.affiliation: Department of Tropical Medicine at the Bernhard Nocht Institute, German Armed Forces Hospital of Hamburg , Germany ; Institute for Microbiology, Virology and Hygiene, University Medicine Rostock , Germany.
authors.forename: Hagen
authors.initials: H
authors.lastname: Frickmann
keywords: PCR; difficult sample matrix; freeze–thawed blood; in-house; malaria; molecular diagnostics; real-time; test comparison