Difference Between LAMP and PCR Test

The key difference between LAMP and PCR test is that LAMP is conducted at constant temperature (60-65⁰C) to produce copies of DNA through amplification, while PCR is conducted using a series of temperature changes to produce copies of DNA through amplification.

LAMP and PCR are both in-vitro amplification techniques used to produce thousands of copies of DNA. The amount of DNA produced in LAMP is much higher than the amount produced in PCR techniques such as RT-PCR. LAMP is a newer technique compared to the PCR technique. But it is technically simple and easy for a trained scientist to perform in laboratory conditions. This makes it a potentially useful technique for the detection of COVID-19. However, RT-PCR is the current standard test for COVID-19. These techniques, while well-known to researchers and clinicians with a background in DNA amplification, still may be relatively unknown to a broader community.

1. Overview and Key Difference
2. What is LAMP Test
3. What is PCR Test
4. Similarities Between LAMP and PCR Test
5. Side by Side Comparison – LAMP vs PCR Test in Tabular Form
6. Summary

What is LAMP Test?

Loop-mediated isothermal amplification (LAMP) for COVID-19 assays start with a collection of samples from the nose or throat using a swab. The samples can also be collected using other methods such as mucus from hard coughing. Like PCR technique such as RT-PCR, the viral RNA in the sample is first converted to DNA, which allows it to be copied. The LAMP reaction is conducted at constant temperature (60-65⁰C).

The amplification of viral DNA incorporating LAMP technology and reagents can be detected when the reaction mixture is turned cloudy due to the production of “magnesium pyrophosphate”. This cloudiness allows easy diagnosis of COVID-19 by scientists and clinicians. The accuracy of test results can be improved by using special fluorescent dyes or colour changing dyes in the reaction mixture. These dyes interact with viral DNA, and the intensity of the light or colour change can be measured to give the number of viral RNA molecules approximately that was initially in the sample.

What is PCR Test?

PCR is a very common scientific technique that has been widely used in research and medicine for 20-30 years to detect DNA. PCR tests are used directly to detect an antigen by detecting viral RNA. Generally, viral RNA is present in the body before detecting antibodies or getting the symptoms of the disease. Therefore, a PCR test can tell whether or not someone has the virus early on. Currently, PCR is the standard test for detecting COVID-19. There are different types of PCR techniques such as real-time PCR, nested PCR, multiplex PCR, hot start PCR and long-range PCR, etc. PCR uses a series of temperature changes to produce copies of DNA through amplification.

RT-PCR is a special version of the PCR technique. It is used when RNA is being detected. It is now used to test COVID-19. RT-PCR is a fairly sensitive and reliable technique. In RT-PCR, once a sample is collected, chemicals are used to remove unwanted proteins, fats, and other molecules, leaving the RNA behind. The test kit enzymes first convert RNA to DNA, which then amplifies viral DNA in order to detect the virus. Fluorescent dyes are typically used to bind to the amplified DNA and produce light. This can be read by the machine to produce the test result.

What are the Similarities Between LAMP and PCR Test?

They are amplifications techniques.
Both produce copied DNA.
They are very sensitive and reliable techniques than immune technique like antibody detection.
They are both used for COVID-19 testing.

What is the Difference Between LAMP and PCR Test?

The key difference between LAMP and PCR tests is that, in LAMP, amplification is achieved using a constant temperature (60-65⁰C), while in PCR, cycling of temperatures is required. Several types of LAMP techniques are available currently. But the most important ones for COVID-19 detection are reverse transcription loop-mediated isothermal technique (RT-LAMP) and transcript-mediated amplification (TMA). Furthermore, different types of PCR techniques also currently available in clinical practice for disease diagnosis such as real-time PCR, RT-PCR, nested PCR, multiplex PCR, hot-start PCR, long-range PCR, etc.

The below infographic lists the differences between LAMP and PCR test in tabular form.

Summary – LAMP vs PCR Test

Loop-mediated Isothermal Amplification is a similar process to PCR tests such as RT-PCR, but it produces more viral DNA copies at a constant temperature. Polymerase chain reaction test is currently the most common and standard form of testing in the world for disease diagnosis, such as the diagnosis of COVID-19. It is seen as fairly reliable. PCR uses a series of temperature changes to produce copies of DNA through amplification. Thus, this summarizes the difference between LAMP and PCR test.

Reference:

1. Culbertson, Alix. “What Are the Different Types of COVID-19 Tests – and Will They Get Us out of Lockdown?” Sky News, Sky, 25 Feb. 2021, Available here.
2. “From PCR to LAMP: The Evolution of Rapid-Testing in Food Safety.” 3M Food Safety News, 27 Mar. 2019, Available here.