A Sodium Rodizonate Lead Testing Kit for Home Use–Valid for Paint and Soil Samples?

Abstract

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°C (room temperature), and one swab each stored at 22°C (cold) and 92°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°C), 77.8% (56°C), and 88.9% (92 °C). The sensitivity of the swabs for testing lead in soil was significantly less: 28.6% at 22°;C, 28.6% at 56°C (room temperature) and 85. 7% at 110°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.