Is There Poison In COVID-19 Rapid Antigen Test Kits?!

Is there a poison called sodium azide in COVID-19 rapid test kits?!

Take a look at the viral claim, and find out what the facts really are!


Claim : There Is Poison In Rapid Antigen Test Kits!

The Internet is now abuzz with the warning by the National Capital Poison Center that COVID-19 rapid antigen test kits contain a poison called sodium azide.

“Sodium azide is a very potent poison,” says the National Capital Poison Center, which is not a government agency, “and ingestion of relatively low doses can cause significant toxicity.”

“When swallowed, sodium azide can cause low blood pressure, dizziness, headache, and heart palpitations. In more severe cases, seizures, loss of consciousness, and death may occur.”

Rapid Antigen Test Poison Fears : Only Dangerous If Misused!

This is yet another example of collective alarmism, based on a relatively innocuous warning by the National Capital Poison Center (NCPC) – an independent, non-profit organisation.

For those who want a quick summary, here are the key points :

  1. Sodium azide is used in some (but not all) rapid antigen test kits as a preservative, in very small amounts.
  2. Sodium azide is poisonous, but the amount is too small in rapid test kits to pose a real danger if accidentally swallowed by adults.
  3. NCPC never said that rapid antigen test kits are dangerous or poisonous, only that the buffer solution in those kits should not be swallowed or dripped into eyes, nose or mouths.


Rapid Antigen Test Poison Fears : What You Need To Know…

For those who want to learn more, here is what you need to know about sodium azide – the “poison” in the COVID-19 rapid antigen test kits.

Fact #1 : NCPC Was Warning About Potential Misuse

The NCPC article on sodium azide in COVID-19 rapid antigen test kits was first published on 18 January 2022, but only went viral 6-7 weeks later.

The author, medical toxicologist Maryann Amirshahi, did NOT claim that these COVID-19 rapid antigen test kits are poisonous, and should therefore be avoided.

She only warned about the dangers of MISUSING the buffer liquid inside rapid antigen test kits. Specifically, the potential dangers of accidentally swallowing it, or dripping it onto eyes or nose or skin.

Some people may accidentally confuse them with medications and apply the drops into their eyes or nose, which may cause irritation. People also may spill it on their skin which can cause skin irritation or chemical burns. Small children may accidentally swallow the contents of the vial or choke on the vial’s small cap.

Fact #2 : Sodium Azide Is Used As Buffer Preservative

In COVID-19 rapid antigen test kits, sodium azide is used as a preservative, to prevent bacterial growth. If you read the instruction sheet of your rapid antigen test kit, you may see warnings like this :

The buffer contains <0.1% sodium azide as a preservative which may be toxic if ingested. When disposed of through a sink, flush with a large volume of water.

Fact #3 : Sodium Azide Only Used In Some Rapid Antigen Test Kits

Sodium azide is not used in all rapid antigen test kits – manufacturers may opt to use other preservatives, like ProClin 300.

If you are worried, you can check the active ingredient list of the test kit. It should tell you whether sodium azide is used in the buffer solution.

Fact #4 : We Should Avoid Contact With Buffer Solution

At no point in time during the RAT / RTK test process, are you supposed to consume the buffer solution, or come into contact with it.

To avoid accidental consumption, the buffer solution is kept is a sealed squeeze bottle or test tube, which is to be disposed off in the provided biological waste pouch / plastic bag.

Perhaps the greatest risk of contact is when people do not follow instructions, and dip their swabs into the buffer solution before swabbing the nasopharynx and/or throat. Or unsupervised children may drip some into their mouth for a taste.

Fact #5 : Toxicity Depends On The Dose

To be clear, sodium azide is a potentially deadly chemical, but we need to remember that the toxicity of any chemical depends on the dose.

Even if you accidentally touch or consume the buffer, please do NOT panic.

As mentioned earlier, the buffer solution may not even contain sodium azide. Even if sodium azide is present, it is a very small amount – less than 0.1% of buffer volume.

There is usually only about 0.35 ml of buffer solution in each test kit, so we are talking about 0.0035 ml (65 mg) of sodium azide.

Based on its LD50 dose of 20 mg/kg (rabbit), a child weighing 10 kg will only be at significant risk on consuming 200 mg of sodium azide – that’s the amount of sodium azide in 3 buffer bottles.

An adult weighing 50 kg will need to consume about 15 buffer bottles to be at significant risk of toxicity. The NCPC article also states as much :

Fortunately, the amount of sodium azide in most rapid antigen kits is much lower than the amount expected to cause poisoning if swallowed by an adult.

Nevertheless, you should still avoid consuming, or coming into contact with the buffer solution. And obviously, you should never let a child handle the test kit!


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Dr. Adrian Wong has been writing about tech and science since 1997, even publishing a book with Prentice Hall called Breaking Through The BIOS Barrier (ISBN 978-0131455368) while in medical school.

He continues to devote countless hours every day writing about tech, medicine and science, in his pursuit of facts in a post-truth world.


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