What is the Difference Between NAAT and PCR

The key difference between NAAT and PCR is that NAAT is a that amplifies genetic material using several ways, including polymerase chain reaction, strand displacement, or transcription-mediated amplification, while PCR is a method that amplifies genetic material using only thermal cycling.

Pathogens are mainly identified by the amplification of their genetic material. Most of the techniques in this area focus on the detection of the genetic material of the pathogen by amplifying specific sequences in real-time. Therefore, the results are produced very fast in the diagnostic context. NAAT, PCR, biosensor, and LCR are several techniques used in laboratories to amplify the genetic material of the pathogen.

CONTENTS

1. Overview and Key Difference
2. What is NAAT  
3. What is PCR
4. Similarities – NAAT and PCR
5. NAAT vs PCR in Tabular Form
6. Summary – NAAT vs PCR

What is NAAT?

Nucleic acid amplification test (NAAT) is a method in molecular biology that amplifies genetic material using several ways such as polymerase chain reaction, strand displacement amplification, or transcription-mediated amplification. Amplification of genetic material can also be done through techniques like a ligation chain reaction and branched DNA reaction (quantiplex b DNA) in the NAAT procedure. NAAT uses the specificity of Watson-Crick base pairing. In the NAAT procedure, a single-stranded probe or primer molecule is hybridized with the target DNA or RNA molecule. Therefore, the design of the probe strand is highly significant to enhance the sensitivity and specificity of the detection. Then, the next step of the NAAT amplifies the genetic material by making many copies of it for detection.

Figure 01: NAAT

NAAT is currently applied for the detection of several pathogens such as Neisseria gonorrhea, Chlamydia trachomatis, Mycobacterium tuberculosis, and SARS-COV2. Moreover, the NAAT test is developed to shorten the window period. The window period is the time period between when a patient has been infected and when they show up as positive by antibody tests. Furthermore, the NAAT screening method was first approved in 1999 by FDA. NAAT has many advantages including, detection of low levels of DNA or RNA, high sensitivity, and high specificity.

What is PCR?

PCR is a method in molecular biology that amplifies genetic material using only thermal cycling. PCR stands for polymerase chain reaction.  It is a test to detect genetic material from a specific organism such as bacteria, fungi, and viruses. In disease diagnosis, PCR detects the presence of a pathogen if the person has a pathogen at the time of the test.  In disease diagnosis, PCR protocol has several steps, including sample collection, DNA extraction, PCR, and sequencing. In testing pathogens, the collected sample is used to extract genetic material (DNA or RNA). PCR procedure requires special chemicals, primers, and enzymes in order to produce millions of copies of genetic material inside the PCR machine called the thermal cycler. Once amplified from the PCR product, the pathogen can be detected. Scientists use special software to interpret the results.

Figure 02: PCR

Furthermore, there are different types of PCR currently used in the research. RT-PCR, Multiplex PCR, RAPD, and Nested PCR are several among them. PCR is useful especially in the detection of pharyngitis (Streptococcl pharyngitis), atypical pneumonia (Chlymydia pneumoniae), measles (Morbillivirus), hepatitis (HBV), and ulcerative urogenital infection (Haemophilus ducreyi).

What are the Similarities Between NAAT and PCR?

• NAAT and PCR are two important molecular biological methods that are used to amplify genetic material.
• Nucleic acids (DNA or RNA) are amplified by both techniques.
• They are rapid and fast techniques.
• Both techniques are currently used for disease diagnosis.
• They are expensive than conventional methods.

What is the Difference Between NAAT and PCR?

NAAT is a method in molecular biology that amplifies genetic material using several methods, while PCR is a method in molecular biology that amplifies genetic material using only thermal cycling. NAAT uses different genetic material amplification techniques such as polymerase chain reaction, strand displacement amplification, transcription-mediated amplification, ligation chain reaction, and branched DNA reaction (quantiplex b DNA). On the other hand, PCR uses different genetic material amplification techniques such as RT-PCR. Multiplex PCR, RAPD, Nested PCR. So, this is the key difference between NAAT and PCR.

The below infographic presents the differences between NAAT and PCR in tabular form for side by side comparison.

Summary – NAAT vs PCR

There are various molecular biological tools used in laboratories to amplify genetic materials. NAAT, PCR, biosensor, and LCR are several such techniques. NAAT is a molecular biological technique that amplifies genetic material using several ways such as polymerase chain reaction, strand displacement, or transcription-mediated amplification. PCR is a method in molecular biology that amplifies genetic material using thermal cycling. Thus, this is the key difference between NAAT and PCR.

Reference:

1. “Nucleic Acid Amplification.” An Overview | ScienceDirect Topics.
2. “Polymerase Chain Reaction (PCR).” Genome.gov.

Image Courtesy:

1. “Transcription-mediated amplification” By Casey Utzinger – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Preparation of the RT-PCR Reaction (05811009) (49869473991)” By IAEA Imagebank – Preparation of the RT-PCR Reaction (05811009) (CC BY 2.0) via Commons Wikimedia

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