Test : Polymerase chain reaction
Indications : PCR is ordered for the following:
• Prenatal /post natal diagnosis of
sickle cell anemia,
hemophilia,
cystic fibrosis, and muscular dystrophy
• Detect oncogene activation in the case of lymphoma and chronic myelogenous leukemia
• Detect the presence of microbes in the case of infections
• Paternity testing
• Identification of forensic samples
The PCR technique permits a million- fold amplification of small pieces of DNA in several hours. The amplification is performed by multiple cycles of DNA polymerizing enzyme in the presence of known sequences. The procedure is automated with programmable heating blocks to cycle the reaction automatically. The technique has unprecedented sensitivity, being able to use small quantity of DNA from a single cell for amplification.
Physiology : The
polymerase chain reaction (PCR) is a revolutionary technique that was developed by Kary Mullis in the 1980s.
PCR is widely used in the field of molecular biology. It employs
DNA polymerase to synthesize new stands of DNA which is complementary to the target sequence (or template).A primer, which is a short sequence of DNA complimentary to the target sequence, is mandatory for amplification of
DNA and this makes it possible for the person employing the technique to control it.
The following components are necessary for PCR:
• DNA polymerase
• Target sequence or template
• Primer
• Nucleotides
Interpretation : The target sequence gets exponentially multiplied during PCR method. After several cycles, the reaction reaches a plateau phase and eventually ceases.
Test Method : PCR technique
Related Tests : Depends upon the amplification required.
References :
1. http://www.ncbi.nlm.nih.gov/genome/probe/doc/TechPCR.shtml