Before samples can be sent to a laboratory they must be __________.

• A. Properly labeled
• B. Sealed and preserved
• C. Field screened
• D. Documented

Answer: (C)

Field screening provides the on-site assessment that determines whether sending a sample for laboratory analysis is warranted. By quickly testing or observing a sample in the field, responders can confirm the presence of a contaminant, identify the appropriate sampling approach, and decide if lab analysis is necessary, making sure the right material is collected and analyzed. This step helps prevent unnecessary lab work and ensures that subsequent submission is meaningful and safe. While proper labeling, sealing and preserving, and documentation are essential for sample integrity and chain-of-custody, they support the lab submission after the decision to send has been made, whereas field screening is the trigger that justifies sending the sample to the laboratory.