The six laboratories in the HHEAR Network of Exposure Analysis Laboratories (also called the Lab Network or Lab Hubs) provide comprehensive, state-of-the-art laboratory services for analysis of human and environmental samples from human health studies. The Lab Hubs can measure environmental exposures, including biological, psychosocial, chemical, and physical factors .
HHEAR provides two categories of analyses in human biospecimens and environmental samples, each of which may be useful in different research contexts.
- Targeted Analysis
Hypothesis-driven analyses of specific contaminants, markers of exposure, and other substances known or suspected to affect health outcomes. Examples include specific pesticides in biological fluids (e.g., blood, urine, saliva specimens, and so forth), biomarkers of tobacco smoke exposure, and heavy metals in environmental samples (e.g., air, water, soil, and so forth). Targeted analyses are typically performed for panels of chemically related compounds.
- Untargeted Analysis of the Exposome
Hypothesis-free exploratory analyses using advanced technologies to discover new associations between chemicals or metabolites and health. Characterization of hundreds to thousands of compounds is possible in a given environmental (e.g., surface water or house dust) or biological (e.g., blood, urine, or saliva) sample. Techniques may include nuclear magnetic resonance (NMR) and mass spectrometry (MS).
Quality Assurance/Quality Control
HHEAR Lab Hubs have a commitment to quality assurance. They participate in national and international proficiency testing programs for trace elements and organic compounds multiple times each year. They also include appropriate blanks, checks for contamination control, internal Quality Control samples, and National Institute of Standards and Technology (NIST) Standard Reference Materials in their analyses.
Limit of detection (LOD) is essential for determining the lowest detectable concentration with acceptable uncertainty. It depends on specimen volume, sample cleanup, instrument sensitivity, and calibration method. The HHEAR Methods/QC descriptions and HHEAR DC reports that provide this information facilitate comparisons between laboratories and pooling.
Details of the QC approaches implemented are outlined in the publications linked below:
- Galusha AL, Merrill L, Palmer CD, Amarasiriwardena C, Parsons PJ. Measurement harmonization and traceability for trace element analyses across the Children's Health Exposure Analysis Resource laboratory network. Environ Res. 2021;193:110302.
- Kannan K, Stathis A, Mazzella MJ, et al. Quality assurance and harmonization for targeted biomonitoring measurements of environmental organic chemicals across the Children's Health Exposure Analysis Resource laboratory network . Int J Hyg Environ Health. 2021;234:113741.