Commonly used molecular biology tests

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Molecular diagnosis is one of the most advanced testing techniques being widely used in medicine today. This technique was born in the late twentieth century based on the PCR amplification method to create PCR reactions, thereby helping to identify and quantify the causative factors of the disease. Currently, this method is widely applied in the diagnosis of diseases such as HIV, HBV, ..

1. What is a molecular biology test?

Molecular biology test is a term used to refer to tests that detect biological markers at the molecular level such as nucleic acid fragments, complete genes or even viral genomes. creature.
The molecular biology test is a PCR gene sequence fusion, a leap forward from the success of gene identification and sequencing techniques. This technique aims to help determine the cause of the disease faster and more accurately to serve the treatment process more effectively.
In molecular biology testing, it is mandatory to use positive and negative controls. Positive controls are controls containing a known target DNA/RNA fragment. Negative controls are controls that do not have a target DNA/RNA fragment to help control cross-contamination when performing reactions.
Molecular biology tests use two main techniques, which are PCR synthesis and Real-time PCR.
PCR synthesis technique: Helps identify bacteria quickly based on PCR reaction. In each PCR synthesis reaction, there will be about 20-35 rounds, after each round, the DNA will be amplified exponentially. In order to have accurate results, in this technique, it is necessary to pay attention to taking samples for testing in appropriate concentrations, correct temperature for each stage. In case of errors, the PCR reaction occurs with low efficiency, it may not even occur, leading to a negative PCR reaction even though the patient's clinical manifestations are very clear. Sometimes, accidentally allowing cross-contamination between controls will result in a positive PCR reaction even if the patient's clinical manifestations are very faint and unclear.
Real-time PCR technique: this technique is almost similar to PCR, but here there is an additional signal recording device when the PCR synthesis reaction is released. Based on comparing the number of rounds of the test sample and the number of rounds of the standard sample achieved in the same reaction time, it will calculate how many times the number of rounds of the test sample is compared to the number of rounds of the standard sample, and then based on that The DNA concentration of the sample was calculated.

2. Application of molecular biology tests in the diagnosis of HBV and HIV

2.1. Molecular biology test in HBV Applied in the diagnosis of HBV, people use molecular biological tests to make HBV automated system load measurement: To help identify HBV bacteria, and also determine the number of HBV infections. the amount of virus before treatment, so it is possible to monitor the amount of the virus during the course of treatment, evaluate the increase and decrease in fluctuations so that it can be treated promptly.
Specimen used: 4ml of EDTA anticoagulant blood or 1.2ml of patient's plasma. Test results will be available in 3 days. HBV measure real-time PCR load: As mentioned above, this technique is similar to PCR but has more equipment to calculate the time of PCR reaction to be able to determine the amount and concentration of samples during this period. This can lead to a more accurate diagnosis of the condition and stage of the disease and the development of causative factors. This is very useful for treatment.
In addition to supporting accurate diagnosis, the following techniques are used:
Quantitative HBV by PCR technique: detecting HBV DNA in blood or in liver cells even when HBsAg has disappeared. This method has high sensitivity and specificity. Genotyping of HBV by sequencing or RFLP techniques. HBV has 8 different genotypes in which genotype is the genotype that is strongly related to disease progression, drug resistance and mutation. Clinical studies have shown that genotype C responds poorly to antiviral drugs but has a higher risk of mutations and cancer than genotype B. Therefore, genotyping is extremely important in determining diagnosis, treatment, and prognosis. Molecular biology testing can also be involved in determining drug resistance in patients with chronic hepatitis B. Similar to the molecular biology test in HBV, for HCV, it is also carried out qualitatively by PCR technique, measuring HCV viral load, determining HCV genotype.

2.2. Molecular biological testing in HIV Just like diagnosing HBV, to diagnose HIV, in learning to use molecular biology to make HIV, automated system load measurement to help quantitatively diagnose the amount of virus that is active. present in the body and then make an accurate diagnosis to have the most optimal treatment plan and help predict the disease.
Specimens for molecular biology testing to diagnose HIV: 4ml of EDTA anticoagulant blood or 1.5ml of blood plasma. Test results will be available 1 week after the test. In fact, in clinical practice, there are many different pathogenic microorganisms, especially new strains such as HIV, HCV, HCV, SARS... or simply fungal strains that if only microbiological testing methods are used. Classical normal birth will not be able to identify or respond slowly to be able to make an accurate diagnosis in time, then, biological testing methods will respond to these factors, helping to diagnose quickly. , accurate and effective for the treatment.
Like in diagnosing HBV, HIV, to diagnose other diseases such as hepatitis C virus, chlamydial fungal disease, adenovirus, dengue virus or mycoplasma... people also use molecular biology tests with PCR synthesis and Real-time PCR for diagnosis.
Molecular biology test is a high testing technique, requiring the operator to have high professional expertise and experience, and the cost of implementation is also quite expensive. Therefore, the indication for molecular biology testing is only given when classical testing techniques fail to respond and cannot provide an accurate diagnosis for the treatment side.
Vinmec International General Hospital is one of the hospitals that not only ensures professional quality with a team of leading medical doctors, modern equipment and technology, but also stands out for its examination and consultation services. comprehensive and professional medical consultation and treatment; civilized, polite, safe and sterile medical examination and treatment space. Customers when choosing to perform tests here can be completely assured of the accuracy of test results.

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