SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

A73
PREVALENCE OF GHB IN SUSPECTED DUI CASES IN MIAMI-DADE COUNTY, FLORIDA
M. Elizabeth Zaney*, WiIJiam D. Gennaro, Gaudelio Saavedra, Bernard W. Steele, H. Chip Walls
University of Miami School.of Medicine - Forensic Toxicology Laboratory
According to numerous police and poison control center reports, GHBis a commonly abused substance in
Miami-Dade County. Therefore, we wanted to study the prevalence of GHB in urine and blood samples
submitted from suspected Driving Under the Influence (DUI) cases to the University of Miami, Forensic
Toxicology Laboratory.
Ninety-one consecutive urine samples received from September-December 2003 (whether positive or
negative for other drugs) were tested for GHB. In addition, a further 114 urine samples, and 74 blood
samples which tested negative for alcohol were tested for GHB and other drugs. Urine samples were
received and stored at 4 'c in containers without preservatives; blood samples were received and stored at
4'C in gray top vacutainertubes with sodium fluoride as a preservative.
A method taken from the Journal of Chromatography B, 792 (2003) 83-87 (Marion Villain, Vincent
Cirimeie, Bertrand Ludes, Pascal Kint=*) was modified utilizing rapid protein precipitation and Iiquidliquid
extraction using 40 microL of sample, 40 microL of deuterated internal standard, 90 microL of cold
acetonitrile and high speed centrifugation. The supernatant was then carefully evaporated to dryness and
the residue reconstituted with 70 microL of BSTF A + 1 % TMCS and heating at 70'C for 25 minutes to
derivatize. Samples were analyzed by GCIMS with a Hewlett Packard Series 5890 GC coupled to an HP
Series MSD run in SIM mode. A 5-point calibration curve ranging from 10 mgfL to 200 mg/L was used to
determine the amount ofGHB present in the specimen.
Of the total 205 urine specimens tested, 5 tested positive for GHB (2.4% positive) with a concentration
range of237 mg/L 2147 mg/L (mean 789 mgfL, median = 484 mgfL). The above 205 samples were
made up of91 consecutive urines of which only 1 was positive for GHB (1.1% positive), and 114 samples
selected by case history, of which 4 were positive for GHB (3.5% positive). 2 blood samples from the 74
tested were positive for GHB (2.7% positive) with concentrations of 147 mgfL and 235 mg/L. A summary
ofthe positive findings can be seen in the Table.
Our findings would suggest that either GHB is not as prevalent as it is thought, or that users are so impaired
that they don't attempt to drive a vehicle until metabolism and/or excretion have resulted in below
detection limit samples, which may account for our low positivity rates. Of interest to note is the
concurrent use ofGHB and Methamphetamine.
Case one Urine
Case two Urine
Case three Urine
Case four Urine
Case five Urine
(These belong to the
same defendant)
Case five Blood
Case six Blood
GHB: 2147 mgfL
Other drue:s present: Ibuprofen
GHB: 609 mg/L
Other dru2:s present: Amphetamine, Methamphetamine, Naoroxen
GHB: 469 mg/L
Other dru2:s Dresent: Amphetamine, Methamphetamine
GHB: 237 mg/L
Other drugs present: Amphetamine, Methamphetamine, MDMA, PPA,
Pseudoephedrine, Dextromethorphan, Ecgonine methyl ester, Oxazepam,
Alprazolam, Hydroxy-Alprazo!am
GHB: 484 mg/L
Other drugs present: Amphetamine, Methamphetamine
GHB: 147 mg/L
Other dru2:s Dresent: Acetone 0.003 g/IOOmL, presumptive positive Amp. class
GHB: 235 mg/L
Other dru2s present: Methamphetamine
Keywords: GHB, GC/MS, DUI
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