Towards a nucleic acid-based diagnosis in clinical parasitology and mycology.

Background: Multiple in-house polymerase chain reaction (PCR) assays for the diagnosis of parasitic and fungal diseases have been reported. Encouraging results have been published to anticipate or improve the diagnosis. However, the absence of standardized methods has led to discrepant results. As a consequence, these tests are not recognized as consensual diagnostic criteria.
Methods: The major breakthrough for improving the results of these methods is the emergence of real-time technologies. This markedly improves the reliability of the PCR results by dramatically decreasing the risk of false positive results due to PCR products carryover. Moreover, the quantitative results provided by these techniques allow to compare rapidly the efficiency of primers, probes, and DNA extraction. Therefore, one can expect a more consensual method to implement comparisons between laboratories. Automated DNA extraction should also be useful to achieve this goal. Whatever sophisticated technology is used, the meaning of detecting nucleic acids in a given clinical sample still needs to be defined. This requires well-designed studies with clinical consensual criteria and PCR techniques that are as similar as possible.
Conclusions: The development of real-time technology should improve our knowledge in order to give the clinicians informative clues for decision-making.