PCR - reveals even hidden infections
In modern medicine, PCR analysis is often prescribed - a polymerase chain reaction. This technique has been used for three decades and still remains one of the most highly sensitive and reliable.
PCR analysis for 12 infections is a way to detect infectious and hereditary diseases that not only have acute manifestations, but are also in a latent state. Many experts believe that the PCR diagnosis should be a mandatory procedure, and do not diagnose the patient without its results.
Sensitivity reveals a disease even before its primary signs appear. PCR - what is it, what advantages does it have and how does it give up correctly?
In what cases is the analysis done?
The method of polymerase chain reaction at the DNA level is used in various medical fields:
- to forensic scientists, he helps identify biological materials, such as hair, salivary fluids, and blood;
- PCR analyzes are used to identify the genotype, for example, in identifying an individual response to drugs that are genetically engineered;
- the technique helps in establishing kinship;
- But most of all PCR analysis is required in medical diagnostics, it helps to detect various kinds of genetic abnormalities and infectious diseases.
How is PCR better than other methods?
Examination of biological materials in this way is used quite often and differs from other diagnostics, first of all, by its high accuracy and ease of delivery.
The stages of PCR analysis.
The advantages include the following:
- an infectious pathogen is detected in the analysis; a DNA or RNA infectious agent is detected;
- the accuracy of the result varies from 99 to 100%, the probability of a false-negative response is very low, and a false positive is almost impossible;
- PCR 12 is the most sensitive method, allowing to detect even single cells of infectious agents;
- having passed the biomaterial, it is possible to take the result of PCR analysis after 4 hours, it is exactly what time is needed to study it;
- the technique allows to detect pathogens without associated symptoms, and early diagnosis contributes to timely treatment;
- the analysis also proved its effectiveness after the illness had already passed.
Over the years of use, PCR analysis has been improved and updated many times. Every year new varieties of polymerase chain reaction research appear, giving a unique opportunity to detect various pathological conditions before their active development.
At the very beginning of the PCR study, not every patient could afford such expensive diagnostics, today its cost is quite acceptable, besides, many laboratories offer such a service.
What infectious pathogens are detected?
No pathogenic pathogen can escape from this diagnostic study.
Decoding can show the presence of the following infectious agents:
- picornaviruses (causing hepatitis);
- yeast-like fungi Candida (culprit candidiasis, the so-called "thrush");
- Chlamydia - in this case, a smear indicates the presence of chlamydia;
- papillomavirus - cause the appearance of benign tumors (HPV);
- viruses that cause the development of herpes infection;
- cancer cells - early detection of a dangerous disease;
- bacteria mycoplasmas - pathogens of mycoplasmosis;
- anaerobic bacteria - if the PCR analysis (smear) indicated their presence, then we are talking about bacterial vaginosis;
- bacteria provoking ureaplasmosis in the urogenital system;
- DNA of the Epstein genomic virus causing the development of infectious mononucleosis;
- Trichomonas vaginalis, the causative agent of trichomoniasis;
- human immunodeficiency virus (HIV, and later - the development of AIDS).
Types of diagnosis
Advantages of the PCR method.
As already noted, in modern medicine several types of PCR diagnostics are used:
- reverse transcriptase polymerase chain reaction - amplification, isolation and identification of one of the specific RNA fragments;
- inverted technique - allows you to identify nearby sequences after placing the DNA into a set of genes;
- asymmetric technique - used to create (amplify) additional chromosomal DNA regions;
- step method - helps reduce the effects of nonspecific binding of oligonucleotides;
- group-specific studies - PCR for related sequences, in one form or among several;
- quantitative analysis of PCR is a real-time study that allows you to monitor the change in the amount of a specific PCR component in each process cycle.
Having received a referral, a completely natural question arises in patients - how are tests for PCR infections being dealt with?
First of all, it is taken into account for what purposes the study is conducted:
- Detection of genital infectious diseases. In this case, a smear is taken from the mucous membrane of the vagina, cervical or urethra, and urine is given. Women are recommended to take an analysis before menstruation or after it.
PCR analysis of chlamydia is the most accurate way to detect these pathogens, since not all studies are able to detect them, and the disease itself is often asymptomatic.
There are several rules for how to pass such an analysis and get a reliable result:
- not to go to the toilet “in a small way” for at least 3 hours before the procedure;
- do not use antibacterial, disinfectant;
- refuse sexual intercourse 2 days before the test;
- Before taking a smear, women should not douche, use suppositories for vaginal administration;
- You should also not take the test during menstrual bleeding.
- Interpretation of the result may be distorted if you take the biomaterial while taking antibiotics or uroseptics.
- Diagnosis of infectious mononucleosis. For research, saliva, blood and its serum part are given.
- PCR analysis for hepatitis C, HIV and other infections. Blood, serum and plasma are donated, and a vacuum system is used, therefore the method is minimally traumatic and the resulting biomaterial is practically isolated from environmental exposure.
A PCR blood test is taken on an empty stomach, it is also impossible to drink before taking it. In addition, a month before the procedure is to refuse to take uroseptikov and antibiotics.
- PCR analysis for tuberculosis.The level of tuberculous microbacteria (Koch sticks) in sputum is detected. The same material is given for the detection of mycoplasmosis and chlamydia in the respiratory form. Sputum is collected in a sterile container.
Why take an analysis during pregnancy?
The future mommy should be tested at registration, including the polymerase chain reaction. Such a laboratory study allows you to identify dangerous diseases before they cause irreparable harm to the health of the woman and the future baby.
The following biomaterials may be collected:
- swab from the walls of the cervical canal;
- blood serum;
- amniotic fluid or chorionic particles (appointed when certain indications).
Timely analysis of smear and other materials will help to avoid possible complications.
The result of PCR analysis.
Decryption of the data occurs fairly quickly, usually in the laboratory give the result the next day.
There are two types of results:
- Negative PCR analysis indicates that no infectious agent has been identified in the biomaterial under study.
- PCR is positive - signals that the patient's deoxyribonucleic or ribonucleic acid is a pathogen.
In addition, decoding includes a quantitative determination of pathogens. This is required for pathological conditions that have arisen against the background of opportunistic microorganisms. This is due to the fact that they begin to negatively affect the state of the body only with excessive amounts.
PCR is a universal diagnosis capable of obtaining a result from any biological material, and decoding not only indicates the presence or absence of the pathogen, but also determines its quantity and name.
Therefore, if an expert recommends the delivery of this analysis, you should not refuse, because you cannot buy health, but it is quite possible to save it.