Viral Tap Water Tested On An Antigen Swab Device, The Results Are Positive, This Is The Scientific Explanation

Siti Nadia Tarmizi (ANTARA)

JAKARTA - Recently, a video spread on social media regarding the experiment of tap water being tested on an antigen swab device and showing positive results.

The spokesperson for COVID-19 from the Ministry of Health, Dr. Siti Nadia Tarmizi, gave a scientific explanation. According to her, all antigen swab test kits that get an official distribution permit in Indonesia must pass the validation test from the Balitbangkes and be re-evaluated every 3 months.

According to WHO requirements, the recommended antigen swab kit is one that has a sensitivity of 80 percent or more and a specificity of 97 percent or more. In the video circulating on social media, it is not clear which tool was used.

"If it is true that the antigen swab device is indeed a brand that has received an official distribution permit from the government", said Siti Nadia to VOI, Monday, July 26.

He explained that the antigen swab examination kit was designed to examine the SARS CoV2 virus antigen from nasopharyngeal swab specimens.

According to Nadia, the lateral flow kit in it is designed to be very complex and sensitive only to detect the protein antigen of the SARS CoV2 virus. The detection paper in the form of a nitrocellulose membrane is very fragile and if the sample inserted is not the result of a nasopharyngeal swab, the membrane will be damaged, the result can be positive (false).

This experiment using tap water has also been carried out on a malaria rapid test device which has a lateral flow kit concept, which should be blood samples. False positive results were also obtained because the examination with this tool should use a buffer solution with a certain pH, and when replaced with tap water, there is a difference in pH and ions so the results can be wrong.

“So, conducting an examination that is not in accordance with the inspection instructions, of course the results will be wrong and the interpretation of the results carried out by non-experts will also be wrong. Because the equipment is damaged, the results that seem positive cannot be interpreted as true positives, that is what is called a false positive”, said Nadia.