Abstract Background Lead exposure remains a significant public health concern, linked to mood disorders, hypertension, pregnancy complications, abdominal pain, and cognitive impairments. Since no safe blood lead level has been established, testing is performed based on exposure risk or clinical necessity. The recent College of American Pathologists (CAP) Blood Lead Survey identified Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) as the most used instrument amongst participants. This study compares the performance of ICP-MS/MS with collision/reaction cell (CRC) mode using oxygen to ICP-MS with kinetic energy discrimination (KED) mode using helium for blood lead analysis. The study objective was to evaluate correlation and potential biases between the two clinically validated methodologies to ensure accuracy and reliability in clinical testing for blood lead. Methods Remnant patient samples, lead-spiked pooled negative samples, quality control (QC) samples, and proficiency testing (PT) samples from CAP were utilized in this study. Samples (20 µL) were diluted with a solution containing 1% ethanol, 5% ammonium hydroxide, 0.02% Triton-X, and 0.01% nitric acid. Following vortexing, 0.5% nitric acid was added to achieve a final dilution of 250-fold for samples analyzed by ICP-MS/MS (Agilent 8900) using on-mass measurement with oxygen in CRC mode. Iridium served as an internal standard. The method was validated as a laboratory-developed test, with analytical parameters such as precision, accuracy, sensitivity, specificity, and carryover analyzed using EP Evaluator. A new total allowable error of 10% or 2 µg/dL was applied. Results Deming regression analysis of 60 samples spanning the analytical measurement range of 1–80 µg/dL yielded a slope of 1.001, an intercept of -0.0891, an R value of 0.9802, and a Deming standard error estimate of 3.2010 for samples analyzed on ICP-MS/MS vs ICP-MS. Precision was assessed using three QC samples at concentrations of 2.5 µg/dL, 14 µg/dL, and 35 µg/dL. The coefficients of variation (CV) for intraday precision across all levels were below 5%, while interday precision values were less than 15%. The limits of detection (LOD) and quantification (LOQ) were determined to be 0.5 µg/dL and 1 µg/dL, respectively. Carryover was negligible, even at the highest concentration of 200 µg/dL, with mean values of 2.03 ± 0.19 for low-low results and 2.18 ± 0.29 for high-high results. Conclusion Lead testing in the pediatric population often presents challenges due to limited blood volume. The newly validated method requires only 20 µL of blood, which reduces volume-related cancellations and allows for multiple analyses from a single sample. While the ICP-MS method uses 50 µL, the reduced volume offers a clear advantage for pediatric applications. The performance of both instruments—ICP-MS and ICP-MS/MS—was comparable, with identical measurement ranges. Although ICP-MS/MS offers advanced capabilities, such as mass-shift filtering of elements in the presence of gases like oxygen, these features make the platform more expensive. However, for lead analysis, these specific capabilities were not utilized. As a result, lead analysis performed on ICP-MS or ICP-MS/MS is fully transferable, making ICP-MS a cost-effective and equally reliable option for this purpose.
Olaniyan et al. (Wed,) studied this question.