Swabs not reliable for detecting lead dust in homes

May 30, 2007

The quick, inexpensive test kits used by homeowners nationwide to detect lead-laced dust are prone to high error rates, according to a University of Rochester study.

Researchers found that 64 percent of the locations that LeadCheck Swabs indicated were safe, actually had hazardous concentrations of lead in dust, according to federal standards. Katrina Korfmacher, Ph.D., an expert on lead poisoning at the University of Rochester Medical Center and first author of the study, warns that people should be aware of the tool's lack of sensitivity and how it might impact the health of children.

"We're very interested in promoting low-cost ways to detect lead at the low levels we now know to be dangerous to children. That's why it was important to evaluate the test," Korfmacher said. "Our concern is that parents or property owners might use these tests and be falsely assured."

Childhood lead poisoning is irreversible. It results from ingesting lead-based paint, lead dust, or contaminated soil.

Some county health departments across the nation use LeadCheck Swabs as an educational tool, recommending the kits to mothers bringing home infants from the hospital. The swabs are sold at many retailers; they cost about $1.30 each when purchased in bulk. They are popular among community groups, landlords and other consumers seeking an inexpensive way to get precise results.

In Rochester, N.Y., several community groups wanted to begin using the tests but agreed to wait until Korfmacher's evaluation was complete. The research was conducted as part of a community "Get The Lead Out" (GLO) project, a collaborative effort between the University and several community groups to prevent lead poisoning. The GLO project is one example of the University's long history in developing innovative approaches to public health problems.

Korfmacher and co-author Sherry Dixon, Ph.D., of the National Center for Healthy Housing in Columbia, Md., report in the June edition of the journal Environmental Research that they tested the LeadCheck Swabs in typical field conditions in Rochester houses, using the manufacturer's instructions. Researchers compared the swabs to standard dust wipes, which are approved by the U.S. Environmental Protection Agency, used by trained risk assessors, and analyzed at certified laboratories. Dust wipes give accurate information, but the required laboratory fees, waiting time, and labor costs that may be prohibitive for some consumers.

The swabs work a little like a home-pregnancy test. According to the instructions, a person rubs the swab onto a small patch of a floor to collect a dust sample. The yellow tip will turn pink or red if lead is present. The instructions say the swabs will instantly detect lead in dust at levels that exceed the EPA standard of 40 micrograms per square foot for floors.

It is not clear why the swabs are failing to detect hazardous levels of lead in dust. Sometimes, the LeadCheck Swabs turned from yellow to shades of brown, which might be confusing to consumers because the instructions do not guide consumers on how to interpret a brown result. The brown tip might result from dirt hiding a red chemical reaction. Another explanation is that household dirt could interfere with the reaction between the dye in the swabs and reactive lead in the dust, researchers noted.

Yet even when results were interpreted conservatively - that is, every swab that did not stay purely yellow was counted as a positive lead result -- the LeadCheck Swabs' probability of correctly identifying dust lead levels above the federal standard for floors was only 72 percent, the study concluded.

LeadCheck Swabs were originally developed to test for lead in paint, Korfmacher said, but more recently they have been promoted for dust, and include instructions for dust testing.

"It's clear from our study that LeadCheck Swabs shouldn't be used to determine if house dust contains lead in excess of the EPA standards, " said Korfmacher, community outreach coordinator for the Medical Center's Department of Environmental Medicine. "However, this test could be a good pre-test for getting professional clearance using dust wipes. If the swab test comes up positive, then you know you have lead and you should clean more before paying for a professional clearance test. But you should never be reassured by a negative test that dust lead levels are safe."
-end-


University of Rochester Medical Center

Related Health Articles from Brightsurf:

The mental health impact of pandemics for front line health care staff
New research shows the impact that pandemics have on the mental health of front-line health care staff.

Modifiable health risks linked to more than $730 billion in US health care costs
Modifiable health risks, such as obesity, high blood pressure, and smoking, were linked to over $730 billion in health care spending in the US in 2016, according to a study published in The Lancet Public Health.

New measure of social determinants of health may improve cardiovascular health assessment
The authors of this study developed a single risk score derived from multiple social determinants of health that predicts county-level cardiovascular disease mortality.

BU study: High deductible health plans are widening racial health gaps
The growing Black Lives Matter movement has brought more attention to the myriad structures that reinforce racial inequities, in everything from policing to hiring to maternal mortality.

Electronic health information exchange improves public health disease reporting
Disease tracking is an important area of focus for health departments in the midst of the COVID-19 pandemic.

E-health resource improves men's health behaviours with or without fitness facilities
Men who regularly used a free web resource made significantly more health changes than men who did not, finds a new study from the University of British Columbia and Intensions Consulting.

Mental health outcomes among health care workers during COVID-19 pandemic in Italy
Symptoms of posttraumatic stress disorder, depression, anxiety and insomnia among health care workers in Italy during the COVID-19 pandemic are reported in this observational study.

Mental health of health care workers in china in hospitals with patients with COVID-19
This survey study of almost 1,300 health care workers in China at 34 hospitals equipped with fever clinics or wards for patients with COVID-19 reports on their mental health outcomes, including symptoms of depression, anxiety, insomnia and distress.

Health records pin broad set of health risks on genetic premutation
Researchers from the University of Wisconsin-Madison and Marshfield Clinic have found that there may be a much broader health risk to carriers of the FMR1 premutation, with potentially dozens of clinical conditions that can be ascribed directly to carrying it.

Attitudes about health affect how older adults engage with negative health news
To get older adults to pay attention to important health information, preface it with the good news about their health.

Read More: Health News and Health Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.