Lab Matters Spring 2019 - Page 12

ENVIRONMENTAL HEALTH A Non-Conventional Matrix: Potential Use of Dried Blood Spots for Biomonitoring by Jennifer Liebreich, MPH, senior specialist, Environmental Health Limited information exists about the extent of human exposure to many environmental chemicals, and the potential toxic health effects of these chemicals in humans are largely unknown. Dried blood spots (DBS) could provide biomonitoring data for populations from whom collecting blood is difficult such as children. Children are recognized as being more susceptible to the effects of potentially harmful environmental chemicals. This article provides an overview of the potential use of DBS for biomonitoring based on a chapter on the topic. Addressing Sample Collection and Sample Sensitivity Concerns In population-based studies, biomonitoring data can be useful to establish background levels of select environmental chemicals and can help identify population groups most highly exposed. The US Centers for Disease Control and Prevention’s (CDC’s) National Health and Nutrition Examination Survey (NHANES) is considered the gold standard of biomonitoring population-based surveillance in the US. However, even in NHANES, biomonitoring data for infants and young children are limited because of age restrictions around collection of blood, making DBS look like an attractive alternative. However, NHANES is not a proponent of including DBS because of technical issues related to difficulty in standardizing collection of capillary blood. Biomonitoring generally requires measuring chemicals at trace concentrations (parts per billion or lower) so biomonitoring with DBS must use analytical methods providing adequate sensitivity and selectivity at such concentrations, which is challenging and 1 2 3 A scientist sorts through DBS punches. Photo: Iowa Department of Public Health Biomonitoring directly measures the actual concentration of environmental chemicals or their metabolites in human biospecimens, and, when used in combination with indirect measures of exposure like questionnaires, biomonitoring data can provide useful information about differences in exposure across geography, race/ethnicity, and socioeconomic status. Blood and urine are most commonly used for biomonitoring. costly. Additional challenges relate to standardization of collection of capillary blood vs venipuncture, and presence of other endogenous and exogenous chemical substances on the DBS. Further analytical considerations for biomonitoring using DBS include limited sample volume; contributions from the filter paper; extraction of biological material from the filter paper; stability; and comparison of data between DBS and serum, plasma or whole blood. DBS offer the promise of making biomonitoring available to a wide range of populations but also represent substantial analytical challenges for both method development and quantitation of analytes (chemicals). While there are concerns with using DBS for biomonitoring of endogenous chemical substances, it has been recently noted that DBS can serve as a good matrix for chemicals such as nerve agents and opioids. Calafat, A. M. and Kato, K. In Dried Blood Spots: Applications and Techniques, Li, W.; Lee, M. S. Eds.; John Wiley & Sons: Hoboken, NJ, 2014; Chapter 10. Seymour C 1 , Shaner RL 2 , Feyereisen MC 2 , Wharton RE 2 , Kaplan P 3 , Hamelin EI 2 , Johnson RC 2 . Determination of Fentanyl Analog Exposure Using Dried Blood Spots with LC-MS-MS. J Anal Toxicol. 2018 Nov 20. Shaner RL 1 , Coleman RM 1 , Schulze N 2 , Platanitis K 2 , Brown AA 2 , Seymour C 3 , Kaplan P 2 , Perez J 1 , Hamelin EI 4 , Johnson RC 1 . Investigation of dried blood sampling with liquid chromatography tandem mass spectrometry to confirm human exposure to nerve agents. Anal Chim Acta. 2018 Nov 29;1033:100-107. 10 LAB MATTERS Spring 2019 PublicHealthLabs @APHL APHL.org