The polymerase chain reaction is a method for rapidly amplifying a specific gene or DNA sequence in vitro, and is also referred to as an in vitro amplification method of a gene. PCR technology is similar to the natural replication process of DNA, and its specificity depends on oligonucleotide primers complementary to both ends of the target sequence.

Basic Information

Specialist Category: Infectious Diseases Inspection Category: Genetic Testing (DNA)

Applicable gender: whether men and women apply fasting: fasting

Analysis results:

Below normal:

Normal value:
no

Above normal:

negative:
Normal: The type and proportion of the flora in the body are normal, and the human body is in a state of dynamic balance and health.

Positive:
A positive indication is the presence of certain viral infections.

Tips: Pay attention to normal eating habits before check, pay attention to personal hygiene. Normal value

The type and proportion of the flora in the body are normal, and the human body is in a state of dynamic balance and health.

Clinical significance

PCR can rapidly and specifically amplify any known gene or DNA fragment of interest, and can easily amplify the target gene in the starting DNA mixture at the picogram (pg) level to a nanogram, microgram, and milligram-specific DNA fragment. Therefore, PCR technology has been rapidly and widely used in various fields of molecular biology.

Abnormal results abnormalities caused by various diseases, such as syphilis: 1 stage syphilis. That is, hard chancre, with an incubation period of 2 to 4 weeks, a dark red hard mass, a shallow ulcer, a cartilage-like hardness, and a swollen peripheral lymph node. 2 second phase syphilis. After 1 to 2 months of primary syphilis, sympathetic rash, rash, pimples, pustular rash, etc. occur in the skin and mucous membranes of the whole body. Mucosal plaques, flat wet phlegm can occur in the mucosa, and the infection is strong. 3 third-phase syphilis. Occurred 2 to 3 years or even 10 years after infection, the skin is a gum-like swelling, and may also involve bone, joint, heart, blood vessels, manifesting aortic inflammation, aortic insufficiency and aortic aneurysm, etc., invading the nerve Spinal cord paralysis, general paralysis (paralytic dementia) and so on.

People who need to be examined: Patients suspected of a particular disease are tested for molecular specificity.

Positive results may be diseases: syphilis, primary syphilis, secondary syphilis precautions

Inappropriate crowd: No.

Forbidden before examination: Pay attention to normal eating habits and pay attention to personal hygiene.

Requirements for inspection: Actively cooperate with the doctor.

Inspection process

PCR consists of three basic reaction steps: denaturation-annealing-extension:

1 Denaturation of template DNA: After the template DNA is heated to about 93 ° C for a certain period of time, the double-stranded DNA of the template DNA double-stranded or amplified by PCR is dissociated to make it a single strand so that it binds to the primer. The round reaction is prepared.

2 annealing of the template DNA and the primer (refolding): After the template DNA is denatured into a single strand by heating, the temperature is lowered to about 55 ° C, and the primer is paired with the complementary sequence of the single strand of the template DNA.

3 primer extension: DNA template--primer conjugate under the action of Taq DNA polymerase, dNTP as the reaction material, target sequence as template, according to the principle of base pairing and semi-reserved replication, synthesize a new complementary to the template DNA strand The semi-reserved replication chain repeats the cyclic denaturation-annealing-extension process to obtain more "semi-reserved replication chains", and this new chain can be used as a template for the next cycle. It takes 2 to 4 minutes to complete each cycle, and the amplification of the gene to be amplified can be amplified several million times in 2 to 3 hours. The number of cycles required to reach the plateau (Plateau) depends on the copy of the template in the sample.

PCR technology has high sensitivity, specificity, simple and rapid operation, and has important application value in many aspects such as life science research, food hygiene, medical treatment, forensic science and environmental monitoring.

Not suitable for the crowd

Taboo population: There are no special taboos.

Adverse reactions and risks

This test generally does not cause special complications and hazards.