Drug Testing in Biological Matrices: Hair and Urine Charles McKay MD FACMT, FACEP, ABIM, MROCC Medical Toxicologist, Medical Review Officer, and Emergency Physician Division of Medical Toxicology, Department of Traumatology and Emergency Medicine Hartford Hospital Associate Medical Director, Connecticut Poison Control Center Associate Professor of Emergency Medicine University of Connecticut School of Medicine
Biomonitoring • Generally applied when presence of a compound or concentration has some meaning • Therapeutic drug monitoring • Quantitative • Detection of illicit drugs • Usually qualitative • “End-of-shift” workplace monitoring • Quantitative comparison to OSHA regulations
Validity of Biomonitoring • Compound has defined source of exposure • Compound is excreted in matrix of interest • There is a control or reference population (if appropriate) • Testing is defined as: • Screening: prone to false positives or false negatives • Confirmatory: interpretation issues related to clinical relevance and limit of detection/reporting
Applications of Hair Testing • Almost any drug could be detected if commercial reason to develop test • For practical purposes, testing is done for: • Usual drugs of abuse similar to workplace “NIDA 5” • Pharmaceutical agents as research tools • Variety of compounds in forensic or research setting • Heavy metals • Inappropriately for number of “environmental contaminants”
Identification of Compound in Hair • Incorporation • Via hair follicle during active growth phase • Drug in perspiration from sweat/sebaceous glands • External contamination • Specimen preparation and washing • Varies by laboratory • May be addressed by measurement of metabolites
Hair Growth Cycle • Generally >90% of the scalp hair is in active growth phase • Average growth rate is ~1 cm/month From: http://www.lahairmd.com/info/hairlossm.htm Similar to diagram found in: Habif TP. Clinical Dermatology: A Color Guide to Diagnosis and Therapy, 2nd edition; CV Mosby Co, 1990
Sampling For Drugs of Abuse • Hair sampling generally done with 50 or more hairs cut at scalp level • Sectioning the hair can be used to compare one period of time to another • Does not reflect previous few days of use • Urine tests generally identify use within last few hours to several days
0 1 2 3 4 cm Scalp End Tip of Hair Sample 1 Sample 2 Sample 3 Example: Hair Testing For Cocaine/Metabolite • Hair Testing for Cocaine: reported results • Sample 1: Positive for cocaine (measured on whole length of hair) at 454 ng/10 mg hair weight • Sample 2 (4 ½ months later): Positive for cocaine in 2nd (15.8 ng/10 mg hair) and 3rd segments (73.5 ng/10 mg hair) only • Sample 3 (5 ½ months after #1): Positive for cocaine (qualitative on whole length of hair) • Hair Testing: Interpretation:
0 1 2 3 4 cm Scalp End Tip of Hair Sample 2 Sample 3 Example: Hair Cocaine And Time of Cocaine Use • Approximate Hair Growth Periods vs. Estimated Time of Cocaine Incorporation • “I used to use, but haven’t used any cocaine in the last 3 months” • Sequential hair samples show decreased concentration over time April 2006 March 2006 February 2006 January 2006 May 2006 April 2006 March 2006 February 2006 January 2006
Urine Samples done every 3-6 days (yellow=negative; black=positive) Positive Urine Sample Example: Use of Hair and Urine Testing For Cocaine Metabolite 0 1 2 3 4 cm • Urine Testing for Cocaine Metabolite • 1/24/06: Positive • 1/26/06 through 6/26/06: Negative Scalp End Tip of Hair Sample 2 Sample 3 TIME
Case Summary • Urine testing reliably identifies cocaine use within previous few days. • In conjunction with decreasing cocaine content in hair over time and no cocaine present in hair that grew over last couple months, there is no clinical laboratory evidence of cocaine use since the positive urine test.
CAVEATS: “But what about…” • …variability in hair growth? • Largest variable is in the length of time in “resting phase” • May lead to appearance of prolonged clearance time for the fraction of hair that is no longer incorporating drug, but also not falling out • …variability in hair color? • Higher melanin (eumelanin vs. pheomelanin) associated with more binding of some (basic) drugs • …variability in hair type/treatment? • Higher incorporation into “damaged” (chemically-treated) hair • Oval or flat hair shafts will curl, raising questions about “true length” (e.g. stretched?) • …external contamination? • Usually indicates significant excretion from pores, so not really “external” contaminant • Low-level findings can be differentiated by proper laboratory steps
So, Is Hair Testing A Good Idea? • Definition of good? • Reliable technique to identify past substance use • Sequential testing may support abstinence and identify relapse • If adequate specimen handling and preparation • May not identify all uses and users at very low levels • resulting in unintended bias • In one study, 15 doses of codeine over 5 days would be detected months later (at recommended federal cutoffs) in: • 100% of those with black hair • 50% of those with brown hair • 0% of those with blond or red hair • Not a practical concern for most cases where drug concentrations are much higher than reporting (or detection) cutoffs
Hair Testing • Collection • Processing • Analysis • Interpretation http://www.testcountry.com/images/hair_test_procedure.jpg
And In Response To Tests… • PassYourTest • UrineClear • PerfectUrine • ClearTest • … • 45 Minute Chewable Tablet • Take the chewable with 48 ounces of water. • Wait 45 minutes. • Urinate 2-3 times during the hour that you are waiting. • The tablet is effective for up to 6 hours. • Helpful Hints: • Avoid toxins for 48 hours before using this product. • Drink water before and after using this product.
So If Your Client Looked Like This… …Then Like This Be very suspicious!
Take Home Messages • GC/MS or LC/MS techniques are reliable in the identification of chemical compounds • Hair analysis is a reasonable mechanism to evaluate long term (months) drug abstinence • There are issues near reporting cut-offs and limits of detection in the interpretation of positive tests that might be addressed by: • Analysis of metabolites • Sequential sectioning • Sample washing techniques • The laboratory and toxicologists can provide assistance in interpretation