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Testing with uSense™ is Quick and Easy

Watch this quick video for instructions on how to use uSense™ for Lead

uSense™ for Lead Frequently Asked Questions

Here you can find some of the questions we are asked most frequently, and perhaps answer an inquiry.

Why am I receiving this lead-in-water test?

Your drinking water provider has partnered with Stemloop to deliver this uSense for Lead test to your residence. As part of EPA regulations, your provider required to make an inventory of residences impacted by lead piping. Water testing with uSense helps the provider complete this inventory and enables the provider to proactively plan for removal of lead piping.

If I test positive for ≥5 ppb lead, what should I do next?

When submitting your results to your drinking water provider through the QR code, you have the option to opt-in to a contact from your drinking water provider. Your provider can point you to your local resources to protect yourself and your family from lead contamination. Common methods of remediation include point-of-use filtration, reverse-osmosis filtration, or lead-service-line removal.

Why does incubation timing matter so much for the test? What should I do if I make a mistake in timing my test?

Incubation timing is crucial to a properly-run uSense test; under or over-incubating samples can lead to false negatives or false positives. The reaction timing is specifically tuned to identify ≥5 ppb lead. If you make a mistake in timing your test, we recommend reaching out to your drinking water system for a replacement test to ensure the most accurate results possible.

What do I do if my test kit is missing a component?

We have rigorous quality standards for uSense for Lead. Most-often, missing components can be found in their associated pouch. That said, mistakes can occur, either at Stemloop HQ or one of our vendor-partners. If you’re missing a component, please utilize the contact form at the bottom of this page.

What are the health impacts of lead in my drinking water?

Lead is a neurotoxic, and there is no safe level of lead in drinking water. For more information, check out the EPA’s Basic Information on Lead in Drinking Water, found here:

Can I order more tests for the rest of my home?

At this time, uSense for Lead is only available through your drinking water provider. Lead in water is a complex problem: while uSense helps identify sources of that problem, it is not able to remove the sources of lead from your home. By partnering with drinking water systems and filtration providers, uSense provides actionable information to deliver safer sips across the United States.

What is the difference between soluble and total lead?

Soluble lead is lead that is dissolved in water. It is odorless, colorless, and visually imperceptible to the human eye. Particulate lead is non-soluble, showing up in a glass of water as tiny metal particulates, sometimes visible to the human eye. For a test to measure “Total Lead,” samples need to be acidified and heated to break down particulate lead. This sample preparation step is not feasible in an at-home setting, so uSense is rate to measure soluble lead only (Note: uSense can be run with a ___% nitric acid digestion to capture total lead when run by trained operator).

How accurate are uSense for Lead tests?

uSense for Lead’s performance is tested under strict laboratory requirements. The test is 95% accurate when run per the instructions. There *are however, some known interferences that can impact test accuracy. Drinking water with a high rate of zinc (≥250 ppb) can result in a high rate of false positive tests; drinking water providers are discouraged from deploying uSense in areas with high zinc concentration.

uSense for Lead is a biosensor, meaning it takes nature’s innate sensing mechanisms and repurposes them. Through a combination of DNA, RNA, and Proteins, the test reacts with drinking water, genetically sensing the presence of soluble lead and visually reporting on the test strip. This is similar to how a Covid-19 or Pregnancy Test operate. Interested in learning more? Check out

I’m having difficulty running my test or reporting my results. Who can I contact for help?

We’re sorry to hear you’re having difficulty with uSense for Lead. We encourage you to watch the instructional video above and read through these FAQs. Should the problem persist, please utilize the contact form at the bottom of this page.

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