The polymerase chain reaction, a review of the practical limitations for human immunodeficiency virus diagnosis.

The polymerase chain reaction (PCR) is a powerful method for the in vitro amplification of specific nucleic acid sequences. As very small amounts of a virus genome can be detected it has obvious diagnostic applications. The background to the reaction and its use for human immunodeficiency virus (HIV) detection are described. The problems likely to be encountered in using PCR as a diagnostic assay (false positives and negatives) and the practical measures which can be taken to overcome them are discussed.