The Harris County Institute of Forensic Sciences’ Forensic Toxicology Laboratory is dually-accredited by the American Society of Crime Laboratory Directors/Laboratory Accreditation Board-International testing program and by the American Board of Forensic Toxicology.
The Institute’s Forensic Toxicology Laboratory is equipped with advanced instrumentation to perform testing services
The laboratory provides analytical services in medicolegal death investigations (postmortem analysis), driving while impaired (human performance alcohol and drug testing), and drug-facilitated sexual assault investigations to support medical examiners, law enforcement agencies, the justice system, and other customers within Harris County.
The Institute’s Forensic Toxicology Laboratory is equipped with advanced instrumentation to perform testing services, and its toxicologists apply this wide variety of instrumental techniques in the course of their casework.
Instrumentation and testing services include:
- Headspace Gas Chromatography (HGC) – Detects the presence of ethanol and other volatile substances.
- Enzyme-Linked Immunosorbent Assay (ELISA) – Screens for common classes of drugs.
- Gas Chromatography-Mass Spectrometry (GC/MS) and Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS) – Confirms and quantifies drugs and their metabolites.
- High-resolution Liquid Chromatography-Time of Flight Mass Spectrometry (LC/TOF-MS) – Screens for routine and novel drugs of abuse.
For more information, read our published work:
Validation of LC-TOF-MS screening for drugs, metabolites, and collateral compounds in forensic toxicology specimens
In addition to the confirmation/quantitation of routine drugs of abuse, the Forensic Toxicology Laboratory identifies and reports the presence of so-called “designer drugs,” such as synthetic cannabinoids (“K2”/”Spice”), synthetic cathinones (“bath salts”) and potent phenethylamine hallucinogens, such as the NBOMe drug class.
Learn about the pathological findings of two fatal 25I-BOMe deaths in Harris County:
Pathological findings in 2 cases of fatal 25I-NBOMe toxicity
Instructions for Collecting and Submitting Specimens for Toxicological Analysis
For full toxicological analysis, it is recommended that the submitting agency provide the following:
- (Blood) A total of at least 14mL of blood collected in two test tubes with sodium fluoride and potassium oxalate preservatives, i.e., gray-topped tubes (best for DWI)
- (Urine) 50mL of urine collected in a urine specimen bottle or urine specimen cup (best for Drug Facilitated Sexual Assault)
Each specimen tube, bottle or cup must be labeled with the following:
- Name of the individual from whom the specimen was collected
- Date and time of collection
- Initials of the individual who collected the specimen
Each specimen tube, bottle or cup should be stored inside a specimen container, such as a cardboard box, envelope or plastic bag. It is acceptable to include multiple specimen tubes, bottles or cups in one specimen container if they all pertain to the same case. The specimen container should be sealed with evidence tape and must be labeled with the following:
- Initials of the individual submitting the specimen container – initials must be written across both the tape and the container
- Name of the submitting law enforcement agency
- Case number
To maintain the integrity of the specimen, a chain of custody should be initiated upon collection and the specimen should be refrigerated as soon as possible.
- Submit specimens to the Harris County Institute of Forensic Sciences Evidence Reception located at
1861 Old Spanish Trail, Houston, Texas (Click here for detailed Evidence Submission & Testing instructions)
- A submission form must be completed at the time of submission and must accompany the submission. Do not attach the form to the specimen container – Click here to download the submission form or request a form from the Institute’s Evidence Receiving staff during regular business hours
to download the submission form or request a form from the Institute’s Evidence Receiving staff during regular business hours.
Result Reporting for DWI Testing
In suspected Driving While Intoxicated (DWI) cases, blood specimens first undergo alcohol testing. If the blood alcohol level is greater than or equal to 0.10 g/100mL, no further testing is performed unless specifically requested. If the blood alcohol level is less than 0.10 g/100mL, drug screening and confirmation is performed.
Identifies and reports the presence of designer drugs such as K2/Spice and bath salts
When the recommended volume of blood or urine is not received, some testing may not be possible. For example, when the specimen sample volume is not sufficient for both drug screening and confirmation tests, positive screening results will be reported as “Presumptive positive.” In these instances, a forensic toxicologist may contact the submitting law enforcement agency to discuss the need for drug confirmation tests. When sample volume is not sufficient for any type of testing, results will be reported as “Quantity not sufficient.”
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