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The polymerase chain reaction (PCR) technique has become an important, widely employed method for the detection and quantitation of the nucleic acid sequences used in the diagnosis and monitoring of genetic and infectious diseases. Much attention has been directed at the problem of false-positive PCR results, which are generally attributed to low-level laboratory contamination of amplified sequences ("carryover"). In contrast, few investigators have commented on the somewhat less frequent, but equally problematic, false-negative PCR results. Investigation of the source of sporadic false-negative PCR reactions found that glove powder, inadvertently introduced into tubes when gloves are changed in an effort to reduce false-positive results, can nonspecifically inhibit each of the major steps in the PCR detection process. Methodologic precautions are recommended to minimize this problem.

The polymerase chain reaction (PCR) technique is a powerful new tool for amplifying target DNA, thus allowing for sensitive detection of specific nucleic acid sequences. One important potential use of PCR involves screening the donated blood supply for transfusion-transmitted viruses. Realization of this goal has been limited by (1) the requirement for multiple, discrete PCR reactions to amplify and detect target sequences of more than one virus, and (2) the lack of a rapid, nonhazardous means for specific detection of one or more PCR-amplified products. We report the simultaneous amplification of three distinct target sequences without discernable loss in sensitivity toward any single target sequence. We also demonstrate very rapid separation and detection of PCR-amplified viral DNA through the use of automated capillary DNA chromatography. Amplified DNA peaks were initially identified by scanning the capillary effluent at ultraviolet wavelengths, while discrimination of human immunodeficiency virus type 1 and human T-cell leukemic virus type I PCR-amplified DNA was accomplished through use of virus-specific, fluorescently labeled primers and probes. These results indicate progress toward an automated system for screening the blood supply for nucleic acid sequences of multiple pathogens.