Table 2.
Sampling periods for the assessment of exposure to persistent and nonpersistent chemicals.
| Preconceptiona | In utero | Perinatal | Postpartum (18–24 months) | Prepuberty (5–6 years) | Midpuberty | Postpuberty | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Persistent chemicals | |||||||||||
| Urineb,c,d | M/F | M (10–15 weekse) | M | x | x | x | x | ||||
| Serumb, f | M/F | M (10–15 weekse) | M | x | x | x | x | ||||
| Whole bloodb, f | M/F | M (10–15 weekse) | M | x | x | x | x | ||||
| Hairb | M | ||||||||||
| Human milkb | 2 weeks – 2 months postpartum | ||||||||||
| Cord serumb | x | ||||||||||
| Cord whole bloodb | x | ||||||||||
| Meconiumb | x | ||||||||||
| Dietary assessmentg | x | M (10–15 weekse) | x | x | x | x | x | ||||
| Home air sampleb, g | x | x | x | x | x | x | x | ||||
| Home composite dust sampleb, g | x | x | x | x | x | x | x | ||||
| Other environmental samplesb, g | Special studies | Special studies | Special studies | Special studies | Special studies | Special studies | Special studies | ||||
| Questionnaireg | x | x | x | —— At 6, 12, 24 and 36 months, then annually until puberty —— | |||||||
| Ecologic analysis (e.g., GIS)g | x | x | x | x | x | x | x | ||||
| Nonpersistent chemicals | |||||||||||
| Urineb,c,d | M/F | M (10–15 weekse) | M | x | x | x | x | ||||
| Serumb,f | M/F | M (10–15 weekse) | M | x | x | x | x | ||||
| Human milkb | 2 weeks – 2 months postpartum | ||||||||||
| Cord serumb | x | ||||||||||
| Meconiumb | x | ||||||||||
| Dietary assessmentg | x | M (10–15 weekse) | x | x | x | x | x | ||||
| Home air sampleb,g | x | x | x | x | x | x | x | ||||
| Home composite dust sampleb,g | x | x | x | x | x | x | x | ||||
| Other environmental samplesb,g | Special studies | Special studies | Special studies | Special studies | Special studies | Special studies | Special studies | ||||
| Questionnaireg | x | x | x | —— At 6, 12, 24 and 36 months, then annually until puberty —— | |||||||
| Ecologic analysis (e.g., GIS)g | x | x | x | x | x | x | x | ||||
GIS, geographic information system; F, father; M, mother; x, period when samples are to be collected.
At the time of enrollment.
Media with extant laboratory methods for likely target chemical agent. Note that for nonpersistent chemicals, multiple samples of biologic specimens may be needed during this time because of possible variability in biologic exposure level due to the short half-life of the chemical. This is particularly important if a critical exposure period is being considered. Alternatively, pilot data may demonstrate the lack of need for frequent sampling if constant exposure occurred in a stable environment.
Timed specimen collection; morning void specimen with creatinine measurement.
Pediatric urine bag or diaper sample for non-toilet-trained children. If not diaper, spot samples or multiple spots.
For example, weeks 10–15 of gestation are a critical period for breast development.
When blood collection is at a young age, piggyback on lead screen at 12 and 24 months that is recommended by the Centers for Disease Control and Prevention.
Environmental sampling, dietary assessment, questionnaires, and ecologic analysis are necessary for persistent chemicals to determine either route or pathway of exposure; otherwise, exposure can be established through the analysis of biologic specimens. Information should be obtained proximate to the sampling period for biologic specimens.