Hair testing can provide useful information about past exposure to drugs, chemicals, toxins and other substances. However, the type of test you choose can matter just as much as the laboratory analysis itself.
Two common options are private hair testing and chain of custody hair testing. Both may involve laboratory analysis of a hair sample, but they are designed for different purposes.
The main difference is how the sample is collected, documented, handled and identified.
Private testing is generally intended for personal or informational purposes where formal evidence handling is not required. Chain of custody testing is designed for situations where the sample and resulting report may need to be relied upon in a legal, forensic, insurance or investigative setting.
The Carlson Company provides both private and chain of custody testing options, allowing clients to select the process that better matches their circumstances.
What Is Private Hair Testing?
Private hair testing is generally chosen when someone wants information about their own potential exposure or wants testing for personal reasons.
For example, a person may want to investigate possible exposure to:
Drugs or medications
Heavy metals
Chemicals
Environmental contaminants
Workplace substances
Other toxins
With private testing, the collection process does not provide the same witnessed forensic documentation required for a formal chain of custody.
This does not automatically mean that the laboratory analysis is unreliable. The key difference is the evidential process surrounding the sample.
The Carlson Company specifically explains that a private submission form does not provide witnessed forensic evidence that may be required for a potential court hearing.
When might private testing be suitable?
Private testing may be appropriate when your main objective is to obtain information for your own understanding rather than to establish evidence for a legal proceeding.
For example, you might be investigating a possible historical chemical exposure and simply want laboratory information to discuss with a relevant professional.
If your situation could eventually become a legal matter, however, it is sensible to discuss the appropriate testing process with the laboratory before collecting the sample.
What Is Chain of Custody Hair Testing?
Chain of custody hair testing involves additional procedures designed to document the identity and handling of the sample from collection through laboratory testing.
The purpose is to create a documented history showing:
Who collected the sample
Who provided or witnessed the sample
When it was collected
How it was sealed
Who subsequently handled it
Where it was stored or transferred
When it reached the laboratory
The Carlson Company describes its chain of custody form as court supportable, while its private submission form is not court supportable.
This distinction becomes particularly important when the test results could be questioned later.
UK forensic guidance also places considerable importance on maintaining an auditable chain of evidence. The Forensic Science Regulator's statutory code states that records should identify people who take possession of evidence, when possession occurred and where the evidence was located.
Why Does Chain of Custody Matter?
Imagine that a hair sample produces an important result.
If the result is later challenged, one obvious question could be:
How do we know that the sample tested by the laboratory was the same sample collected from the individual?
A properly maintained chain of custody helps answer that question.
It creates an audit trail around the evidence and reduces uncertainty about its identity and handling.
UK government guidance explains that a chain of evidence provides an audit trail showing where evidence has been and how it has been handled. It also notes that poor evidence handling can lead to challenges regarding the evidence and may affect its use in court.
The same principle applies to forensic hair samples. The laboratory result is only one part of the overall evidential process. Collection, identification, packaging, transportation and documentation can also matter.
How Is a Hair Sample Collected for Chain of Custody Testing?
Proper collection is important regardless of the reason for testing, but formal chain of custody testing involves additional documentation and witnessing.
According to The Carlson Company's hair collection guidance, full length head hair should be collected from the scalp line without including roots or follicles. The sample should be approximately the diameter of a pencil, with the scalp end wrapped in aluminium foil before being placed into a clean envelope. The witness then signs and dates across the seal.
This helps preserve the orientation and integrity of the sample.
The Carlson Company also recommends a dated photograph of the donor during collection for identification purposes.
For more information, readers can review the Hair and Nail Sample Collection Guide before arranging a test.
Does Chain of Custody Make the Laboratory Result More Accurate?
Not necessarily.
This is an important distinction.
Chain of custody primarily concerns sample identity, documentation, security and evidential integrity. It does not automatically make the analytical method itself more accurate.
A laboratory still needs appropriate analytical methods, suitable equipment, quality procedures and a sample that meets testing requirements.
Therefore, it is better to think of chain of custody as protecting the credibility and traceability of the evidence, rather than changing the chemistry of the laboratory test.
For information about laboratory testing and available services,
you can explore The Carlson Company's forensic laboratory testing services.
When Should You Choose Private Hair Testing?
Private testing may be worth considering when:
You want information for your own records
You are investigating possible historical exposure
You do not currently expect to use the results in court
You want to understand whether testing may be appropriate before pursuing a formal investigation
Your situation does not require witnessed forensic collection
However, circumstances can change.
If there is any possibility that your results could become part of a legal dispute, employment matter, insurance investigation or formal forensic case, discuss this with the laboratory before choosing a private collection process.
Starting with the wrong collection method could mean that you need to repeat the testing later.
When Is Chain of Custody Testing More Appropriate?
Chain of custody testing is generally more appropriate when the result may need to function as evidence.
Potential situations include:
Legal disputes
If hair testing forms part of a legal dispute, formal documentation may become important.
Forensic investigations
Investigators may need to demonstrate exactly how a sample moved from collection to laboratory analysis.
Insurance matters
Some insurance related investigations may require stronger documentation than a private test provides.
Court related testing
If the result is expected to be presented in court, the collection and handling process should be established in advance.
The UK Forensic Science Regulator's guidance emphasises appropriate labelling, packaging, preservation, transportation, storage and documentation of forensic exhibits.
Can a Private Hair Test Be Used in Court?
You should not assume that it can.
A laboratory result and a court supportable evidence process are not necessarily the same thing.
The Carlson Company explicitly distinguishes between its private submission process and its chain of custody process, stating that the private form does not provide witnessed forensic evidence intended for potential court use.
If legal proceedings are a possibility, explain this before collecting the sample. Your solicitor, legal representative or relevant authority may also have specific requirements that need to be followed.
Frequently Asked Questions
Is private hair testing the same as forensic hair testing?
No. Private testing is generally intended for personal or informational purposes, while forensic testing involves additional procedures designed to protect the evidential value of the sample.
Does chain of custody guarantee that a test will be accepted in court?
No. Chain of custody helps document the identity and handling of evidence, but legal admissibility depends on the circumstances, jurisdiction, collection procedure, laboratory processes and other factors.
Does hair testing require the hair root?
Not necessarily. The Carlson Company states that its hair and nail testing does not require roots or follicles and recommends full length hair samples for exposure history.
Can I switch from private testing to chain of custody testing later?
It may be necessary to collect a new sample if the original collection did not meet the requirements for formal evidence handling. If legal use is possible, discuss the appropriate collection process before taking the sample.
How long can hair provide an exposure history?
Hair grows at an average rate of approximately half an inch per month. The Carlson Company explains that around half an inch can represent approximately 30 days, while two inches may represent roughly four months of exposure history.
Conclusion
The difference between private hair testing and chain of custody hair testing is primarily about the purpose and handling of the sample.
Private testing can be appropriate when you want laboratory information for personal reasons. Chain of custody testing is more appropriate when the results may need to support a legal, forensic, insurance or investigative matter.
The most important step is to choose the correct process before collecting the sample. A properly collected and documented specimen can help reduce avoidable questions about identity, handling and sample integrity later.
If you are unsure which option is appropriate for your circumstances, speak with the testing laboratory before submitting your sample.
Need help choosing the right hair testing process? Contact The Carlson Company to discuss your requirements and find out whether private or chain of custody testing is appropriate for your situation.
You can also Contact The Carlson Company to discuss your testing requirements or explore its toxicology and chemical exposure testing services.
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