There are two processes that are used on a large scale to diagnose viral infections which are the immunoassays and polymerase chain reaction (PCR). These two methods are effective for analyzing varying conditions which require different criteria each to cater to a wide array of patients.
Polymerase Chain Reaction (PCR)
The PCR is a routine technique performed in a laboratory which amplifies small amounts of DNA or RNA samples into larger volumes. These larger volumes are easier for diagnosis and analysis. A viral DNA sample is taken from a patient through a swab test or by drawing blood. The sample is then sent to a laboratory for specialist testing to be analyzed.
RNA viruses like SARS-CoV-2 require the PCR as an extra step in the efforts of producing an additional DNA template (cDNA) from RNA. This takes place by including a reverse transcriptase (RT) enzyme which is how RT-PCR is derived.
PCR starts by putting in short sequences of DNA which are primers that connect the strands of viral DNA. The DNA with double strands will then be recognized and linked up by a polymerase enzyme that is thermostable. The enzyme behaves as a molecular photocopier which aids in the extension of the sequence to produce a complete complementary strand.
Immunoassays work differently from molecular techniques. They detect any presence of immune proteins on a highly precise level. The assays are wide-ranging and cover different formats but mainly comprise of an antibody or antigen that is stagnant on a surface. They link antibodies or antigens that are virus-specific from a sample taken from a patient. A reporter protein is then added to possibly detect an immune signal that is virus-specific to diagnose any presence of an infection.
PCR in COVID-19 Application
Patients may or may not display any symptoms whereas some may contract a mild fever, cough, and critical conditions like pneumonia or respiratory failure. We are fortunate to have the publication and rapid sequencing of the SARS-CoV-2 chromosome which started as early as January as well as RT-PCR primers that are given ready access to medical facilities all over the world.
The RT-PCR benefits the medical industry through its high sensitivity and fast speed. As soon as a swab is taken, a sample can immediately be sent to the laboratory for results which can be generated within just hours. Furthermore, just a tiny amount of RNA is needed before it can be amplified, and the testing is sensitive enough to detect a virus from a given sample.
Immunoassays in COVID-19 Application
Immunoassays do present greater advantages as compared to PCR. Antibodies and antigens are relatively more stable in comparison against RNA, thus making them less prone to getting spoiled during transportation and storage. This is important to help reduce potential false-negative test results.
Immunoassays are able to detect infections that have taken place previously. For patients who have recovered from COVID-19 and given a clearance, their viral DNA is completely wiped out after a certain timeframe. Antibodies, on the other hand, can persist much longer in a person’s bloodstream even after several years. They can then be used to indicate the infection level and the period of time since it was last exposed. These factors are important for contract tracing.
Contact us at EnMed MicroAnalytics for antibody testing. Do not leave the health, welfare, and future of yourself and loved ones to chance. Be sure!