What is PCR sensitivity? (with photos)

In a PCR procedure, a DNA sample is basically unzipped to create two strands and then encouraged to replicate, creating multiple copies of the DNA strand.

The polymerase chain reaction (PCR) is a technique used to amplify a sample of DNA. PCR sensitivity refers to how effectively a sample is amplified. Sensitivity is both a blessing and a curse for people who use this technique to prepare DNA for analysis. A number of things can influence the sensitivity of PCR, and researchers have conducted a number of studies to learn about the things that can play a role in sensitivity and how those things can affect the outcome of a test.

Scientists use the PCR technique to amplify a DNA sample.

Simply put, in a PCR procedure, a DNA sample is basically unzipped to create two strands and then encouraged to replicate, creating multiple copies of the DNA strand. This technique takes advantage of the way DNA replicates in the real world to create a large sample that can be used for analysis. Using PCR, people can amplify a small sample to examine a specific area of ‚Äč‚Äčinterest and to identify specific segments of DNA that may be a cause of interest or concern.

PCR sensitivity can help find DNA that may only be present in traces of a sample.

The extreme sensitivity of this process means that PCR is very vulnerable to contamination. If the person administering the test contaminates the sample with DNA from their body, such as pet hair or skin chips, the sample will be distorted. PCR sensitivity is a major concern in laboratories because people want to avoid contaminated samples if possible.

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The sensitivity of PCR is also a boon, however. The ability to amplify anything and everything in the sample means that a PCR can be used to find DNA that may only be present in small amounts in a sample. For example, someone with a chronic condition such as HIV may have a very low viral load, making it difficult to find copies of the virus in the patient’s blood. Thanks to the sensitivity of PCR, even very low viral loads are detectable, because a single copy of the virus will be amplified when run by PCR.

In forensic PCR analysis, the sensitivity of PCR can be critical as it can allow a technician to identify foreign DNA in a sample that could provide a clue to a crime. Analysis of ancient DNA samples can also be complicated or facilitated by sensitivity. The ability to amplify a small sample of DNA can be a blessing when only a limited sample is available, such as when a forensic anthropologist has only one tooth to work with when identifying someone, but it also means that a limited sample can be compromised beyond use by contamination. .

Many things can influence the sensitivity of PCR. The precise process used in the lab is a factor, as are the compounds used to process the sample. This is why technicians must carefully document the process so that someone studying the results can look for problematic techniques or chemicals used that could invalidate the results or cast them in doubt.

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