How Much Sodium Azide Is In COVID-19 Tests? | Safety Facts Guide

Home kits use tiny vials of extraction buffer to move the sample across the strip. Many brands add sodium azide to that buffer as a preservative. People often ask, “how much sodium azide is in covid-19 tests?”—this guide answers that with numbers you can verify.

Sodium Azide In COVID-19 Tests: Typical Percentages

Manufacturers disclose sodium azide as a percentage by weight in the buffer or device. Across popular rapid antigen kits, published instructions and safety sheets list concentrations that cluster between 0.0125% and 0.1% w/v. Below is a side-by-side look at several kits and the percentages they report.

Brand/Test	Listed Sodium Azide In Buffer	Source
CLINITEST Rapid COVID-19 Antigen	0.05% (tube); 0.02% (device)	FDA EUA IFU
Flowflex COVID-19 Antigen Home Test	0.02% (buffer)	Package insert
BD Veritor At-Home COVID-19 Test	<0.1% (buffer)	HCP insert
BinaxNOW COVID-19 Antigen Card	~0.0125% (reagent)	SDS
CareStart COVID-19 Antigen	Contains sodium azide (percent not always stated)	IFU
Generic Rapid Antigen Buffer (MSDS)	0.05% (tube); 0.02% (device)	MSDS
BD Veritor Controls	<0.1% (listed with controls)	IFU
Range Across Kits	0.0125%–0.1%	Medical review

Percent values tell you the strength in grams per 100 milliliters. A 0.05% solution contains 0.05 g per 100 mL, which equals 0.5 mg per mL. Because the vial volume is small, the total mass per test is also small.

How Much Sodium Azide Is In A Vial, In Milligrams?

Two numbers matter: the percentage on the label and the milliliters in the vial. Most home kits include around 0.3–0.5 mL of liquid. Converting percent to mg/mL lets you estimate the actual amount per vial:

1. Convert percent to mg/mL: multiply the percent by 10. Example: 0.05% × 10 = 0.5 mg/mL.
2. Multiply by the vial volume: 0.5 mg/mL × 0.3 mL = 0.15 mg in the vial.

Using that math, typical kits hold roughly 0.04–0.5 mg per vial, depending on the brand and fill volume. That range matches the percentages published by manufacturers and medical reviews.

How Much Sodium Azide In Covid Test Kits — Practical Guide

Why include this preservative at all? Sodium azide keeps microbes from growing in the buffer, which helps the chemistry run as expected. The amounts are fractional percentages, and the liquid stays sealed until use. Even so, treat the vial with care, keep it out of reach of kids and pets, and wipe any spills right away.

Brand Notes And Safe Handling Tips

• CLINITEST: The device and tube list 0.02% and 0.05% respectively. Open over a sink or paper towel to catch drips.
• Flowflex: The buffer is described as a detergent solution with 0.02% sodium azide.
• BD Veritor: The tube formulation states less than 0.1% sodium azide.
• BinaxNOW: A safety sheet lists 0.0125% sodium azide in the reagent fluid.
• CareStart: The insert warns that reagents contain sodium azide; treat the buffer as you would a household chemical.
• Other kits: Some inserts mention only a preservative without a number; assume a small percentage unless the maker states “no sodium azide.”

Need quick references while testing? Save the poison center number (1-800-222-1222 in the U.S.) and keep the kit’s insert nearby for first-aid steps. If anyone swallows buffer or gets it in the eye, act right away using the guidance below and call for expert advice.

First Aid, Disposal, And Practical Precautions

If Someone Is Exposed

Do not make the person vomit. For eye contact, rinse with lukewarm tap water for 15–20 minutes. For skin contact, wash with soap and water and change out of wet clothing. For swallowing, sip water and call a poison specialist or local emergency number. Keep the product label on hand so the exact kit and ingredients can be confirmed.

Small splashes on skin or brief eye contact can sting or irritate. Swallowing larger amounts can cause low blood pressure, headache, or nausea. Medical teams will decide what care is needed based on the dose and symptoms.

Disposal And Plumbing Notes

Drop used swabs, cassettes, and empty vials in household trash unless local rules say otherwise. Avoid pouring leftover buffer into metal plumbing, since azides can react with lead or copper. If a spill reaches a sink, flush with plenty of water to dilute.

How We Convert Percentages To Milligrams

Here’s a quick reference table that converts common label strengths and vial volumes to an estimated total mass. These values use percent-weight-per-volume math (g per 100 mL).

Label Strength	Vial Volume	Approx. Sodium Azide (mg)
0.0125%	0.3 mL	0.0375
0.0125%	0.5 mL	0.0625
0.02%	0.3 mL	0.06
0.02%	0.5 mL	0.10
0.05%	0.3 mL	0.15
0.05%	0.5 mL	0.25
0.1%	0.5 mL	0.50

Are All COVID-19 Tests The Same?

No. Percentages vary across brands and even across lots, and a few lab-based tests use different preservatives. Always read the current insert for the kit you have in hand, since manufacturers can update reagents over time. Many inserts also list the exact fill volume, which helps you estimate the total mass using the table above.

Safe Use Checklist

• Open the vial on a flat, well-lit surface away from kids and pets.
• Twist the cap slowly to avoid splashes; keep tissues or paper towel nearby.
• Use only the liquid provided; do not add tap water or any substitute.
• Close the vial between steps unless the procedure tells you to leave it open.
• After testing, wipe the area and wash your hands with soap and water.
• Store kits at the temperature listed on the box; avoid car glove-boxes and bathrooms with steam.

How Much Sodium Azide Is In COVID-19 Tests? Brand Details And Math

Putting the pieces together: published instructions show 0.02% for Flowflex, about 0.05% for certain CLINITEST tubes, less than 0.1% for BD Veritor, and about 0.0125% for BinaxNOW reagent fluid. With the usual 0.3–0.5 mL per vial, that translates to roughly 0.04–0.5 mg across brands. These tiny quantities still deserve care, but they are measured in fractions of a milligram.

How These Amounts Compare To Toxicity Data

Published medical literature estimates a fatal adult dose around 700 mg total (about 10 mg/kg), with nonfatal exposures reported from 0.3 to 150 mg. The tiny masses in home kit vials—generally below half a milligram—sit far under those numbers. That said, dose matters per kilogram, and kids or pets can be affected by smaller amounts. The safest move is to prevent contact and call experts quickly if a swallow or splash occurs.

Why Dose Per Kilogram Matters

Body size changes risk. A toddler who drinks an entire vial receives more sodium azide per kilogram than an adult who gets a small taste. Rapid onset low blood pressure is the main concern after larger ingestions. Because symptoms can start within minutes, a quick call for guidance helps families decide the next step.

Two Trusted References To Keep Handy

You can read a clear, plain-language overview in the Poison Control guidance. For product-specific details, see manufacturer instructions such as the FDA CLINITEST instructions, which show preservative percentages in the buffer and device.

How To Check Your Kit’s Ingredients

Look for the “extraction buffer” or “reagent” line in the insert. Many companies publish the exact percent next to sodium azide; others list it as a preservative without a number. If no percent is printed, search the kit name plus “IFU” or “instructions for use,” then download the current PDF from the maker or regulator. Numbers can change after updates or re-authorizations, so match the document to your box’s part number.

Do Any Tests Avoid Sodium Azide?

Yes. A subset use different preservatives or buffers. Some documents list borate salts or EDTA instead. Because formulations vary, never assume two brands are identical. The simplest approach is to check your insert, note the volume, and keep the conversion table above in mind when estimating milligrams.

Storage And Spill Cleanup

Store the box at room temperature on a high shelf. Keep vials capped until needed. If buffer spills on a counter, absorb with paper towel, then wipe the area with plenty of water and dish soap. If a spill reaches a sink, run the tap for several minutes to dilute and carry liquid through non-metallic trap parts. Avoid mixing leftover buffer with other chemicals or cleaners.

Why You’ve Heard Warnings

Poison centers reported calls from families who mistook the small vials for eye drops or medicine, especially during the busy testing periods. Public advisories aim to prevent those mix-ups, not to scare people away from testing. Keep the kit pieces in the tray until use, open only one vial at a time, and discard packaging right after the result window is read.

Quick Recap

Most home antigen kits list sodium azide between 0.0125% and 0.1% in the buffer or device. That equals about 0.04–0.5 mg per vial, based on typical volumes. Read your kit’s insert, keep the vial away from children, and follow first-aid steps promptly if exposure happens.