Techniques for pathogen testing

Molecular diagnostics uses DNA, RNA or proteins to test for disease. The molecular diagnostic techniques that LCT uses include polymerase chain reaction (PCR) and serology.

PCR tests for the presence of DNA or RNA from a specific disease-causing pathogen. PCR is a very sensitive technique that amplifies or copies specific nucleic acids. LCT uses a version of PCR called high-resolution melting curve analysis. This technique copies the DNA or RNA and also determines the amount present in a sample – it’s faster and more sensitive than conventional PCR.

Serology tests for antibodies – proteins that are produced by the immune system in response to disease-causing pathogens. If antibodies to a specific pathogen are present, it shows that there is a previous or current infection.

Transcript

Olga Garkavenko (Living Cell Technologies)
Our laboratory is a cutting-edge molecular diagnostic laboratory in this field. So we are using the most innovative testing in our lab, and this is PCR – polymerase chain reaction – but it’s a very new modification – high-resolution melting curve analysis.

PCR, this is a very interesting method. It allows you to identify the viral particles, say, in a biological sample, for instance, blood plasma. So what it does is it would find a specific nucleic acid and then will amplify it up to a million times, so it would enhance sensitivity of the detection method probably a million times. That’s why it’s very convenient and very applicable to the diagnostic when we are dealing with low copies of the virus, with the low viral load in samples of the patient or donor. High-resolution melting curve analysis would allow much more precise detection, much more precise quantification of the virus in a very short period of time, so analysis, instead of taking several hours like with conventional PCR, on some occasions would be finished say in 1 hour.

We’re using serology as a confirmatory test. Serology is the testing for the evidence of past infection. It looks for antibodies – special proteins that our immune system would develop for a particular pathogen. So it’s very quick and a very convenient method especially when you’re dealing with high numbers of samples.

PCR or polymerase chain reaction is quite different. It’s looking for the presence of the nucleic acids of the actual virus. But we are using both techniques. They would confirm each other. If we would find some positive case, we would definitely run both serology and PCR.