Use and applications of nucleic acid probes in the clinical laboratory

The use and availability of nucleic acid probes are significantly greater than they were three to five years ago. This increased utilization has resulted because of numerous changes in molecular genetic procedures. First, the sources of probes have shifted from cloned genomic and cDNA fragments to single-strand oligonucleotides and RNA or "riboprobes." These newer probes offer defined composition and capability to create separate sense and anti-sense strands. Second, an increased variety of labeling techniques provide more ways to incorporate isotopic and nonisotopic species into these nucleic acid fragments than before. Third, the advent of nucleic acid amplification forecasts the ability to detect sub-attomol quantities of target nucleic acids, which could not be detected by classical hybridization methods. Fourth, more-sensitive signaling systems (e.g., chemiluminescence) now available will also contribute to the lowering of detection limits. Fifth, alternative sample-processing methods will shorten the time required to perform these assays. Finally, coupling these newer molecular probe procedures with automation will lead to improved precision and reliability and promote their introduction into the clinical laboratory as routine procedures. Additional factors such as clinical correlation, cost analysis, etc. will stimulate clinical laboratory personnel to participate further in development and use of these procedures.