The components of the Viral Transport Medium include guanidine salt, EDTA, phenol red, buffer solution, etc. The main functions of Viral Transport Medium is to inactivate the virus, crack the protein shell of the virus, and preserve the nucleic acid.

• Guanidine salt: The most important ingredient in Viral Transport Medium is guanidine salt. Commonly used guanidine salts include guanidine isothiocyanate and guanidine hydrochloride. The guanidine salt can destroy the protein shell on the surface of the virus, release nucleic acid, can be used for nucleic acid detection to confirm whether is infected. The Viral Transport Medium can also inactivate the virus, avoiding the risk of spreading during the sampling, transportation and detection process.

• EDTA: The second Viral Transport Medium component is EDTA component (Ethylene diamine tetraacetic acid), the main function is to inhibit the degradation of nucleic acid, improve the quality of nucleic acid detection, and ensure the accuracy of subsequent virus amplification.

• Buffer: The main function of the buffer is to maintain the acidity and alkalinity (pH value) in the tube

• Phenol red: The acid-base indicator "phenol red" is the reason why the Viral Transport Medium liquid is red. The indicator is red when neutral, purple when the solution becomes alkaline, and yellow when acidic. If the Viral Transport Medium deteriorates, or is contaminated by bacteria, the pH value changes, and it will change from red to yellow. 'Red' indicates that the Viral Transport Medium is within the validity period. At the same time, when the nucleic acid testing personnel add the sample to the colorless sample well, the red color can also allow the testing personnel to observe whether the addition is wrong or whether there is any omission.