LAMP: A CDC Program to Ensure the Quality of Blood-Lead Laboratory Measurements

Abstract

Context: The Lead and Multielement Proficiency (LAMP) program is an external quality assurance program promoting high-quality blood-lead measurements. Objectives: To investigate the ability of US laboratories, participating in the Centers for Disease Control and Prevention (CDC) LAMP program to accurately measure blood-lead levels (BLL) 0.70 to 47.5 &mgr;g/dL using evaluation criteria of ±2 &mgr;g/dL or 10%, whichever is greater. Methods: The CDC distributes bovine blood specimens to participating laboratories 4 times per year. We evaluated participant performance over 5 challenges on samples with BLL between 0.70 and 47.5 &mgr;g/dL. The CDC sent 15 pooled samples (3 samples shipped in 5 rounds) to US laboratories. The LAMP laboratories used 3 primary technologies to analyze lead in blood: inductively coupled plasma mass spectrometry, graphite furnace atomic absorption spectroscopy, and LeadCare technologies based on anodic stripping voltammetry. Laboratories reported their BLL analytical results to the CDC. The LAMP uses these results to provide performance feedback to the laboratories. Setting: The CDC sent blood samples to approximately 50 US laboratories for lead analysis. Participants: Of the approximately 200 laboratories enrolled in LAMP, 38 to 46 US laboratories provided data used in this report (January 2017 to March 2018). Results: Laboratory precision ranged from 0.26 &mgr;g/dL for inductively coupled plasma mass spectrometry to 1.50 &mgr;g/dL for LeadCare instruments. All participating US LAMP laboratories reported accurate BLL for 89% of challenge samples, using the ±2 &mgr;g/dL or 10% evaluation criteria. Conclusions: Laboratories participating in the CDC s LAMP program can accurately measure blood lead using the current Clinical Laboratory Improvement Amendments of 1988 guidance of ±4 &mgr;g/dL or ±10%, with a success rate of 96%. However, when we apply limits of ±2 &mgr;g/dL or ±10%, the success rate drops to 89%. When challenged with samples that have target values between 3 and 5 &mgr;g/dL, nearly 100% of reported results fall within ±4 &mgr;g/dL, while 5% of the results fall outside of the acceptability criteria used by the CDC s LAMP program. As public health focuses on lower blood lead levels, laboratories must evaluate their ability to successfully meet these analytical challenges surrounding successfully measuring blood lead. In addition proposed CLIA guidelines (±2 &mgr;g/dL or 10%) would be achievable performance by a majority of US laboratories participating in the LAMP program.