Main Body

Clinical Chemistry and Hematology Laboratories

About Toxicology at the Wadsworth Center

• Toxicology Proficiency Testing Database

In New York State, there are approximately 250 laboratories providing drugs of abuse testing. Laboratories that perform drugs of abuse testing for the purpose of diagnosis and treatment participate in the clinical toxicology program.The laboratories that provide drugs of abuse testing for the purpose of pre-employment or workplace drug testing, where the services follow chain-of-custody protocols, participate in the forensic toxicology program.In order to appropriately challenge the varied drug testing services laboratories offer, the toxicology section of the proficiency testing program has developed three modules:routine drug testing, case studies and directed quantitations.The routine drug testing module consists of four urine samples, which may contain any of the following drugs:amphetamines, barbiturates, benzodiazepines, benzoylecgonine, ethanol, fentanyl, methadone, opiates, phencyclidine, propoxyphene, THC-cannabinoids, and tricyclic antidepressants.The matrices used for the case studies can be urine, serum or whole blood specimens.These samples are designed to further challenge the analytical toxicology services.Included with the case study is a clinical presentation narrative, which aids in focusing the analysis.The directed quantitations consist of two urine specimens; an accompanying form lists the analytes to be quantitated.The samples for directed quantitation are only shipped to laboratories that perform quantitative confirmatory analysis.

 

The samples are prepared by the toxicology section in the Clinical Chemistry/Hematology Laboratory.The specimens consist of human urine, serum or whole blood supplemented with the analytes.The proficiency test samples are shipped out three times a year and a schedule for the current year is available by clicking on the following link: 

Go to Clinical Laboratory Evaluation Program

The module(s) a laboratory receives depends upon the permit category it holds.The chart below shows the permit categories and the module(s) that are shipped:

Permit Category	Routine Drug Testing	Case Studies	Directed Quantitation
Clinical Toxicology-Limited to Initial Testing
Clinical Toxicology-Comprehensive
Forensic Toxicology-Limited to Initial Testing
Forensic Toxicology-Comprehensive

Laboratories having applied for the Forensic Toxicology-Comprehensive or the Clinical Toxicology-Comprehensive permit category must maintain acceptable methods for the confirmation of presumptive positive screens on-site. For all permit categories except Forensic Toxicology-Comprehensive, the result is reported as positive or negative.Acceptable performance is achieved by reporting the correct qualitative result.The most recent initial screen critiques are available online.

Laboratories having applied for the Forensic Toxicology-Comprehensive permit category are required to perform quantitative analysis.A mean is calculated from participant values using a robust statistical technique and is used as the target value.The acceptable limit is ±20% or ±2 S.D. (whichever is greater) of the target value.The quantitative results are summarized in a statistical report.The most recent statistical summaries can be found online.

Laboratories must earn a minimum overall score of 80% to achieve satisfactory test event performance.Failure to achieve a satisfactory score for an analyte or test event in two of three consecutive events results in unsuccessful performance.

---

Please mail comments, corrections or suggestions to: clinchem@wadsworth.org