A sodium rodizonate lead testing kit for home use--valid for paint and soil samples?
BACKGROUND
The presence of lead in consumer products has become an important health issue. Lead Check is a home test kit promoted to detect lead on any surface at government action levels with 96.6% accuracy. Validation of this kit's sensitivity and specificity is necessary because false negatives may give the user a false sense of security, while false positives may result in unnecessary concern.


METHODS
Aliquots of paint and soil samples submitted to a county health department were collected. Lead Check kits were used to analyze these samples in accordance with manufacturer's instructions. Each sample was tested with three reagent swabs; one stored at 56 degrees C (room temperature), and one swab each stored at 22 degrees C (cold) and 92 degrees C (hot) for 24 hours. Results were compared to quantitative results obtained from the health department's lead testing laboratory.


RESULTS
The sensitivity of the swabs for testing lead in paint was 91.7% for all three temperatures with a specificity of 88.9% (22 degrees C), 77.8% (56 degrees C), and 88.9% (92 degrees C). The sensitivity of the swabs for testing lead in soil was significantly less: 28.6% at 22 degrees C, 28.6% at 56 degrees C (room temperature) and 85.7% at 110 degrees C. The specificity for testing lead in soil was 100% for all temperatures.


CONCLUSIONS
The claim that Lead Check can detect lead in paint at government action levels (0.5% lead) appears to be accurate; however, the claim that this kit can reliably detect lead in soil at 1000 ppm was not verified. The swabs were found to maintain their ability to detect lead even if not stored under ideal conditions.
Scharman
E J
EJ
West Virginia Poison Center, West Virginia University School of Pharmacy, Charleston 25304, USA.
Krenzelok
E P
EP
D004781:Environmental Exposure; D005069:Evaluation Studies as Topic; D007202:Indicators and Reagents; D007854:Lead / Q000032:analysis*; D010150:Paint / Q000032:analysis; D011933:Reagent Kits, Diagnostic; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012987:Soil / Q000032:analysis
D007202:Indicators and Reagents; D011933:Reagent Kits, Diagnostic; D012987:Soil; D007854:Lead