Fecal Sampling - doe-std-1128-98

DOE-STD-1128-98

Precautions are necessary if a lab uses an aliquot for analysis and extrapolates the

aliquot result to the total sample. The aliquoting procedure should be tested using

spiked samples to assure that it is representative.

A quality control (QC) verification program should exist for laboratory analyses,

including use of known blank samples and samples spiked with known quantities of

radioactivity. Ideally, the samples should not be distinguishable by the analytical

laboratory from actual worker samples. The number of QC verification samples may

range from 5% to 15% of the total samples processed by a large-volume program; a

small program focused on submittal of special samples following suspected intakes

may have a much higher percentage of controls. An additional QC provision may be

to request the analytical lab to provide results of their in-house QC results for

independent review.

There are no standard or regulatory requirements for bioassay sample chain-of-

custody provisions, nor has there been consensus on their need. Tampering with

samples has not been a widely reported or suspected problem. Site-specific chain-of-

custody requirements should be based on balancing the need with the resources

required to implement them. Some sites have no chain-of-custody requirements

associated with bioassay sample collection. At other sites, a simple seal placed on a

sample container following collection by the subject worker is an effective means of

providing a small degree of chain-of-custody. At the more complex level would be

strict accountability requiring signature of issue, certification of collection, and

signature of submittal.

Procedures describing details of the bioassay program should be documented. These

procedures should include a description of sample collection, analysis, calibration

techniques, QC, biokinetic modeling, and dose calculational methods used.

5.5.3

Fecal Sampling

A fecal sampling program must be designed to ensure worker cooperation, whether

collecting samples at home or in the workplace. Since the frequency of fecal voiding

varies greatly from person to person, the sample collection program must be

adaptable. Flexibility in sample dates is important. It is suggested that when a fecal

sample is required, the worker be provided with a kit and instructed to collect the

sample, noting the date and time of voiding on the sample label. This practice can

reduce the likelihood of unsuccessful samples. If multiple samples are required (for

example, to collect the total early fecal clearance following an acute inhalation

exposure), the worker may be given several kits and told to collect the next several

voidings, noting the date and time of each.

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