Non-isotopic probe labelling: advantages and drawbacks for diagnostic specifications.

Nucleic acid probes represent an essential tool for molecular investigation in both basic and applied research. In this last field they are particularly useful for diagnosis or prognosis and even for therapy. In the diagnosis, the nucleic probes theoretically allow to reach a sensitive level of reliability never obtained before. Nevertheless, the use of nucleic probes in diagnosis routine need to respect a drastic schedule of conditions since: nucleic probes have to be perfectly specific. nucleic probes have to be sensitive and to allow the detection of less than 100 femtogram of nucleic acid target in routine. In some cases this threshold has to be less than 1 femtogram (for instance HIV detection cases). Nucleic probes have to be absolutely reliable without risk to obtain false positives or negatives. Complete hybridization results must be obtained fast (within 2 or 3 hours in most cases). Labelling systems of nucleic acids must be non-isotopic. Numerous labelling systems, isotopic or non isotopic, have been described during the last fifteenth years. Since some time, the non-isotopic labelling is allowing to contemplate a widespread diagnostic use of it in daily medical, veterinary and agronomy practice. At the present time, some old labelling systems are ahead and new systems are going to be developed worldwide. The future of nucleic probes for the diagnosis needs to assume the schedule of conditions described above. In addition, uses and results obtained with these probes have to be standardized (what is not done yet). Automation and use of amplification of target nucleic acids must be viewed for some applications.(ABSTRACT TRUNCATED AT 250 WORDS)