Fecal Sampling - STD-1128-98master0143

DOE-STD-1128-98

Guide of Good Practices for Occupational Radiological Protection in Plutonium Facilities

hazardous material shipping requirements. Freezing samples can preserve them, but plateout

and sedimentation upon thawing should still be expected.

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 an 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 an in the workplace. Since the frequency of fecal voiding

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

Flexibility in an 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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