Top 10 Laboratory Records Every Criminal Defense Attorney Should Request in a DUI Blood Test Case
A laboratory report may be only a few pages long, but the scientific evidence behind that report can span hundreds of pages of documentation. In many DUI and criminal toxicology cases, the laboratory report tells only part of the story.
The real questions often lie in the underlying records. Our forensic scientists routinely review laboratory discovery to determine whether accepted scientific standards were followed throughout the testing process. While every case is unique, there are ten categories of records that frequently provide valuable insight into the reliability of forensic laboratory results. These records can reveal whether proper quality assurance procedures were followed, whether instruments were functioning correctly, and whether laboratory conclusions are scientifically supported.
Why Laboratory Discovery Matters
Many attorneys receive a laboratory report and assume they have everything the laboratory relied upon.
In reality, a standard toxicology report may be only a few pages, while the complete laboratory file can contain dozens—or even hundreds—of pages of supporting documentation.
These additional records often contain the information necessary to independently evaluate the reliability of the laboratory's conclusions.
1. Laboratory Accreditation and Applicable Standards
One of the first questions to ask is whether the laboratory is properly accredited—and equally important—which standards govern its work.
Attorneys often confuse accreditation organizations with standards-writing organizations.
Understanding the distinction between organizations such as:
ANSI
ANAB
AAFS
ASB
ABFT
helps determine what requirements actually apply to the laboratory's testing procedures.
Accreditation demonstrates competence, while published standards establish the scientific expectations laboratories should follow.
2. Quality Control Records
Quality control forms the foundation of every reliable forensic laboratory.
Laboratories should maintain documentation showing:
Positive controls
Negative controls
Process controls
Acceptance criteria
Failed quality control events
Ongoing monitoring of QC performance
These records demonstrate whether the analytical system was performing within acceptable limits when a sample was tested.
If quality control fails, the reliability of every associated case may be called into question.
3. Calibration Records
Analytical instruments must be calibrated using certified reference materials.
Attorneys should request documentation showing:
Calibration certificates
Pipette calibration
Balance calibration
Glassware verification
Traceability documentation
Equipment service records
An instrument can only produce accurate measurements if the equipment used to prepare and measure samples is itself accurate.
4. Method Validation
Before a laboratory introduces a new analytical method—or modifies an existing one—it should validate that method.
Validation studies typically evaluate:
Accuracy
Precision
Bias
Carryover
Interference studies
Detection limits
Quantitation limits
Dilution integrity
Without proper validation, there is little assurance that a testing method performs as intended.
5. Analyst Qualifications
Scientific results are generated by people—not just instruments.
Understanding who performed each step of the analysis can be important.
This includes determining:
Who prepared the sample
Who operated the instrument
Who processed the data
Who reviewed the results
Who signed the final laboratory report
Analysts should possess appropriate education, training, competency documentation, and, where applicable, professional licensing.
6. Instrument Maintenance Records
Even the most sophisticated analytical instrument requires regular maintenance.
Attorneys should request maintenance documentation covering both before and after the analysis, including:
Preventive maintenance
Consumable replacement
Column changes
Service records
Repair history
Instrument performance depends upon proper maintenance throughout its operational life.
7. Chain of Custody
Scientific testing begins long before a sample enters the laboratory.
Chain of custody documents establish:
Who possessed the evidence
When transfers occurred
How evidence was stored
Whether documentation is complete
Gaps or inconsistencies may raise important questions regarding sample handling and integrity.
8. Batch Sequence and Vial Verification
Samples are rarely analyzed individually.
Instead, laboratories typically analyze groups of samples together.
Reviewing the batch sequence helps determine:
Which samples were analyzed together
Placement of calibration standards
Placement of quality controls
Order of unknown samples
Possible contamination events
This information can provide important context when evaluating laboratory performance.
9. Chromatograms
Laboratory reports summarize numerical results.
Chromatograms show the underlying scientific data.
These instrument outputs allow experts to evaluate:
Peak identification
Peak integration
Baseline stability
Unexpected compounds
Potential interferences
Instrument performance
Sometimes issues apparent in chromatograms never appear in the final laboratory report.
10. Documented Laboratory Issues
Every laboratory experiences occasional problems.
The important question is whether those issues were documented, investigated, and appropriately resolved.
Attorneys should consider reviewing:
Corrective action reports
Internal audits
External audit findings
Accreditation assessments
Quality assurance investigations
Public disciplinary records where available
Historical issues may provide valuable context when evaluating laboratory reliability.
Don't Forget the Blood Collection Process
Not every scientific issue originates inside the laboratory.
Sample integrity begins at collection.
Improper blood draw techniques—including incorrect tube fill volume, hemolysis, improper storage, or delayed preservation—may affect the reliability of subsequent laboratory testing.
Independent review should examine the entire evidentiary chain, beginning with collection and continuing through final analysis.
Independent Scientific Review Makes a Difference
Laboratory reports often answer only one question:
What result did the laboratory obtain?
Independent forensic review asks a much more important question:
Can the science supporting that result withstand careful scrutiny?
At Medusa Analytical, our experts evaluate every stage of the forensic process—from blood collection and quality control through calibration, validation, chromatography, and laboratory documentation—to determine whether scientific conclusions are supported by accepted analytical practices.
Because when scientific evidence influences someone's liberty, every detail matters.