Laboratory Testing Cut-offs & Methods

DRUGS OF ABUSE - URINE SCREENING & CONFIRMATION METHODS

OVERVIEW

The following is an explanation of RTL's urine screening and confirmation procedures/cut-off levels. The routine cut-off levels listed below may periodically change. Note: some cut-off levels may differ for your agency. The analytical methods used by RTL are scientifically accepted and approved by the U.S. Department of Health and Human Services.

• Screening Cut-off Levels and Methods
• Confirmation Cut-off Levels and Methods

URINE SCREENING METHODOLOGY
In order to determine if a urine specimen is negative or positive for drugs of abuse, all specimens are initially screened by an enzyme immunoassay (EIA) procedure. Specimens that yield an EIA response below the specified cut-off are reported as "none detected". Any specimen that shows an EIA response at or above the specified cut-off is considered "presumptive positive" for a particular drug or drug class. Based on your agency's account, presumptive positive specimens may be confirmed by a second method prior to reporting positive results. (See "urine confirmation methodology" below).

	SCREENING CUT-OFF LEVELS BY EIA        Cut-off levels updated periodically.
	Drugs of Abuse		EIA Cut-off
	Amphetamine		1000 ng/mL
	Methamphetamine		1000 ng/mL
	Barbiturates		200 ng/mL
	Benzodiazepines		200 ng/mL
	Buprenorphine		5 ng/mL
	Cocaine Metabolite (Benzoylecgonine)		300 ng/mL
	Ethanol		0.04gm/dL
	Methadone		150 ng/mL
	Methadone Metabolite		150 ng/mL
	Methaqualone		300 ng/mL
	Opiates (morphine and codeine)		300 ng/mL
	Oxycodone		300 ng/mL
	Phencyclidine		25 ng/mL
	Propoxyphene		300 ng/mL
	THC (cannabinoids)		20/50 ng/mL*

*Agency has the ability to choose cut-off levels indicated.

URINE DRUG TEST CONFIRMATION METHODOLOGY

Analytical methods of confirmation include thin layer chromatography (TLC), radioimmunoassay (RIA), gas chromatography (GC), or gas chromatography/mass spectrometry (GC/MS). The subsequent confirmatory procedures are performed on a second independent portion of the original urine specimen.

	CONFIRMATION CUT-OFF LEVELS BY PROCEDURE      Cut-off levels updated periodically.
	Drug		TLC		RIA		GC/MS
	Amphetamines  - Amphetamine  - Methamphetamine  - MDMA  - MDA		< 500 ng/mL < 500 ng/mL < 500 ng/mL < 500 ng/mL				100 ng/mL 100 ng/mL 100 ng/mL 100 ng/mL
	Barbiturates		< 500 ng/mL				200 ng/mL
	Benzodiazepines				200 ng/mL		50 ng/mL (LC/MS/MS)**
	Buprenorphine						0.5 ng/mL
	Cocaine metabolite (Benzoylecgonine)				150 ng/mL		50 ng/mL
	EtG						100 ng/mL (LC/MS/MS)**
	EtS						25 ng/mL (LC/MS/MS)**
	Fentanyl						5 ng/mL
	GHB						10 mcg/mL
	6-Monoacetylmorphine						5 ng/mL
	Marijuana Metabolite (THC-COOH)				25 ng/mL		5 ng/mL
	Methadone		< 500 ng/mL				100 ng/mL
	Methaqualone		< 500 ng/mL
	Opiates     - Total Morphine     - Codeine     - Hydrocodone     - Hydromorphone     - Oxycodone		< 500 ng/mL < 500 ng/mL 1000 ng/mL 1000 ng/mL 1000 ng/mL				100 ng/mL 100 ng/mL 100 ng/mL 100 ng/mL 100 ng/mL
	Phencyclidine (PCP)						10 ng/mL
	Propoxyphene		< 500 ng/mL				200 ng/mL
	Tricyclic Antidepressants     - Amitriptyline     - Nortriptyline     - Imipramine     - Desipramine     - Maprotiline     - Doxepin						50 ng/mL 50 ng/mL 50 ng/mL 50 ng/mL 50 ng/mL 100 ng/mL
	Alcohol (GC-FID)***						.02 gm/dL

** Test performed by Liquid Chromatography / Mass Spectrometry / Mass Spectrometry
*** Test performed by Gas Chromatography Flame Ionization Detection.

URINALYSIS ADULTERATION/SPECIMEN VALIDITY EXAMINATION

RTL’s Standard Operating Procedures (SOP's) require that each urine specimen be examined for signs of adulteration. This examination includes the following:

Physical Examination: Color, excessive foaming, excess sediments, or unusual odor are noted. If adulteration is suspected, this is noted on the final report.

Analytical Examination: Upon request, pH, creatinine (tested by default) and specific gravity are run to aid in determining specimen validity or possible adulteration.

The Resource Library includes information available in our printed Reference Guide, delivered to all new clients. To download a PFD of our Reference Guide, click here.