Chain of Custody in Phlebotomy: Legal and Forensic Blood Draws

What Chain of Custody Means

Chain of custody is the documented, unbroken record of who handled a specimen from the moment it was collected until it was tested and disposed of. Every person who touches the specimen signs for it. Every transfer is recorded. The point is to prove in a legal proceeding that the specimen was not tampered with, contaminated, or switched.

This matters because the results of these tests can cost someone their job, their freedom, or their parental rights. Courts require proof that the sample in the lab is the same sample that came from the person being tested.

When Chain of Custody Applies

Not every blood draw requires chain of custody procedures. These protocols apply when the results may be used in a legal or regulatory context:

• Workplace drug testing (pre-employment, random, post-accident, reasonable suspicion)
• Alcohol testing (DUI cases, workplace incidents)
• Forensic blood draws (criminal investigations, court-ordered testing)
• Paternity testing
• Probation and parole compliance testing
• Child custody proceedings
• Sports doping investigations

Routine clinical draws for a patient's medical care do not require chain of custody. If you are unsure whether a draw requires COC procedures, ask the ordering provider or your supervisor before you collect.

The Custody and Control Form

Federal workplace drug testing uses a standardized document called the Federal Drug Testing Custody and Control Form, commonly called the CCF. This is a multi-copy carbonless form with specific fields that must be completed at every stage of specimen handling.

The CCF includes:

• Donor's name and identification
• Collection site information
• Collector's name and certification number
• Date and time of collection
• Specimen ID number (must match the label on the tube)
• Donor certification that the specimen is their own
• Signatures at every transfer point
• Lab accession and results section

Non-federal chain of custody collections (many legal and forensic draws) use facility-specific or agency-specific forms, but the principles are the same: document every hand the specimen passes through.

The Collection Procedure

Chain of custody collection is more structured than a routine draw. Here is the standard sequence:

1. Verify identity. The donor must present valid government-issued photo ID. You document the ID type and number on the CCF. This step is non-negotiable.
2. Complete the CCF with collection site information and donor details before drawing.
3. Collect the specimen in the donor's presence. The donor must be able to observe the entire collection process.
4. Label the specimen immediately in front of the donor. The label must have the specimen ID number that matches the CCF.
5. Apply tamper-evident seals to the tubes. These are adhesive labels or tape that cross the cap and tube. If the seal is broken, it is visible. The donor must initial the seals.
6. Have the donor sign the CCF certifying the specimen is their own and that the seals are intact.
7. The collector signs and dates the CCF, certifying the collection occurred as documented.
8. Package and seal the specimen for transport. The specimen may not be left unattended at any point.

Tamper-Evident Seals

Tamper-evident seals are a physical proof mechanism. They are adhesive labels placed across the specimen tube cap and tube so that opening the tube breaks or visibly damages the seal. The donor must initial across the seal, which also personalizes it.

If a seal arrives at the lab broken, the specimen is rejected. A broken seal means someone may have tampered with the sample, and the integrity of the result cannot be guaranteed. The specimen must be recollected.

Transfers and Signatures

Every time the specimen changes hands, both parties sign the chain of custody documentation. The person releasing the specimen and the person receiving it both sign, with the date and time. This creates an unbroken paper trail.

Common transfer points:

• Collector to courier or shipping
• Courier to laboratory receiving
• Laboratory receiving to testing bench
• Testing bench to storage or disposal

If a specimen is shipped by commercial carrier, the carrier tracking documentation becomes part of the chain of custody record.

What Breaks Chain of Custody

Chain of custody is broken when any of the following occur:

• The specimen is left unattended
• A transfer is not signed and documented
• A tamper-evident seal is broken
• The specimen label does not match the CCF specimen ID
• Identity verification was not performed or documented
• The collector was not present during the entire collection
• Documentation is altered or incomplete

Consequences of a Broken Chain

When chain of custody is broken, the test result cannot be used in a legal proceeding. A defense attorney can challenge the result on the grounds that the sample could have been tampered with. Courts regularly throw out toxicology results with broken chain of custody.

Practically, this means recollection. The donor must be tested again under proper conditions. In cases where time matters (blood alcohol level in a DUI, for example), recollection is not always possible. The test result is simply lost.

For the phlebotomist, breaking chain of custody can result in professional discipline, termination, and in some cases legal liability if the broken chain contributed to an unjust outcome.

Practice Questions