However, PCR does come with some limitations. Because this molecular assay replicates a large number of genes, even small contamination within the sample can cause a false-positive response. So, only a trained medical professional may conduct accurate PCR tests at a lab. Additionally, designing the correct primers takes a significant amount of time because some combinations of sequences are possible in the genes that are not the targeted gene. Without careful consideration, the test results can display false-positive results. Even after designing the correct primers, they sometimes bind to regions of DNA that are similar to the primer, allowing for another false-positive response. Moreover, the test could take up to a day or two because PCR requires advanced technology, making it necessary to send the sample to a lab for testing. This also makes the test more unaffordable and expensive compared to the Antigen test.