Biotechnology for Health (Biomedical Innovations)

Unit 7: Problems 7-8: Forensic Autopsy & Independent ProjectBI 7.1Biomedical Innovation: forensics & independent research

Maintain chain of custody

Keep an unbroken, signed handoff trail for every piece of evidence so it can be trusted later.

Builds on (2 levels back)inferred · high confidence

Labeling a sample with unique ID, date, and collector: A custody trail only works if each item already has a unique label; without it you cannot tell which row of the log is about which item.
Recording events in time order: Chain of custody is a time-ordered list of handoffs, so you first need the habit of logging who did what, when, in sequence.

Prerequisites are inferred: pending teacher review.

Re-learn the skill with worked practice and clear examples.

Chain of custody is an unbroken, signed log of every person who handled a specimen, when, and why: from collection to analysis.

Step 1: Define it

Chain of custody is the documented handoff trail for evidence: each time a specimen changes hands, both the person releasing it and the person receiving it sign with the date and time.

Step 2: Read the log

Read each row top to bottom. The receiver on one row should be the releaser on the next row, with no gaps in time. That overlap is what makes the trail unbroken.

Step 3: Spot a break

If a row's times do not connect to the next row's, or a handoff has no signature, the chain is broken and the evidence can be challenged.

Practice

In the custody log shown, which row shows a break in the chain of custody?

Reviewed

Row	Released by	Received by	Date/Time
1	J. Ruiz (collector)	M. Chen (transport)	06/22 09:10
2	M. Chen (transport)	A. Patel (intake)	06/22 10:30
3	A. Patel (intake)	(no signature)	06/22 11:00
4	A. Patel (intake)	L. Gomez (analyst)	06/22 13:15

A.Row 1
B.Row 2
C.Row 3
D.Row 4

Show the worked solution ▾

Answer: C. Row 3

Step 1: Check each handoff: Every row should name both who released the specimen and who received it.
Step 2: Find the gap: Row 3 lists a releaser but the 'Received by' is blank, so no one signed for taking the specimen: the trail is broken there.

Why it's right: Row 3 has no receiving signature, so there is no record of who held the specimen at that handoff: an unbroken chain requires both signatures.

Why the others miss:

A: Row 1 names both the collector and the transporter with a time.
B: Row 2 connects cleanly to Row 1 and names both people.
D: Row 4 names both A. Patel and the analyst with a time.

Aligned to BI forensics: chain of custody · reading level ~grade 9

Where you'd see this

A lab rejects a sample whose custody log skips from the collector straight to the analyst with no intake handoff in between.

Careers that use this

Medical Laboratory Technician: Signs specimens in and out so each test result can be traced back to a labeled, logged sample.

Video library

Watch: Maintain chain of custody

Chain of Custody

CSInetwork · ~5 min

Guided notes

Fill these in as you work through the lesson.

Big idea: Chain of custody is the documented handoff trail for a piece of evidence: every person who held it, when, and why: kept unbroken from collection to analysis.

Key terms: write the meaning

Chain of custody (the documented handoff trail):
Specimen (the sample being tracked):
Handoff (one person passing the item to the next):
Unique ID (what keeps two specimens from being confused):

The rule

A custody log is trustworthy only when every is recorded with the date, the person, and a reason, with no in the timeline.

Check yourself

Why does each handoff need both a release and a receive signature?
What does a missing row in the middle of a custody log tell a reviewer?
How does a unique specimen ID keep one sample from being mixed up with another?

Work one example

You collect a tissue specimen at 9:10, hand it to a lab tech at 10:30, and the tech logs it into storage at 11:00. Write the three custody-log rows you would record so the trail is unbroken.