THCA in Head Hair: A Comparison with

Fingernail

Conflict of InterestEmployees of USDTL

• Privately held company• Commercial laboratory• Sells hair testing services• Internally funded• No role in:

• Study design• Data collection• Analysis• publication

Marijuana usage trendsTHCA in hair and nailValidation w 10 fg/mg LODComparison hair and nailConclusions

OBJECTIVES

Most common illicit drug2010-17.4 M past month users2009 factor 376k ED visits

Trends of Marijuana Use

Trends of Marijuana Use23 States and DC

LegalizedMedical use Decriminalized Both

Trends of Marijuana Use

Daily use 12th

graders 6.5% from

5.1% in 2007

12th graders negative

perception of regular use

44.1%, lowest since

1979

What Do We Look For?

THC THCA

Detection Windows

#1 ENVIRONMENTAL EXPOSURE

SMOKE

TRANSFERANCE CONTACT

FUMES

HOW DO DRUGS GET INTO THE HAIR?

HOW DO DRUGS GET INTO THE HAIR?

#2 SWEAT AND OIL

THESE DRUG AND METABOLITE CONTAINING FLUIDS BATHE THE HAIR

SHAFT

HOW DO DRUGS GET INTO THE HAIR?

#3 THE BLOOD

Specimen Type: Why Fingernail?

Anatomy of Fingernail

NAILMATRIX

NAIL PLATE

NAIL BED

Fingernails Are Made of Keratin

o Keratin:  fibrous structural protein of hair, nails, horn, hoofs, wool, feathers, and of the epithelial cells in the outermost layers of the skin. The polypeptide chains of keratin are arranged in parallel sheets held together by hydrogen bonding.

~Encyclopedia Britannica

Fingernails Are Made of Keratin

o These keratin sheets stack on top of each other, giving the nail thickness and length, making adulteration of the specimen difficult.

Incorporation of Drug

Biomarker:  a measurable substance whose presence is indicative of ingestion or exposure to substances of abuse (SOA).

o Biomarkers can be found in nails as early as 1-2 weeks after substances of abuse are ingested.

o The time period during which drug ingestion can be detected depends on the substance used, the amount used, and personal metabolism.

Biomarker Absorption

Single point Calibrator – 50 fg/mgLOQ – 20 fg/mg LOD – 10 fg/mgULOL – 1000 fg/mgControls 20, 62.5, and 400 fg/mgRobust – minimum 22 consecutive days

THCA Validation Specs

LOD 10 fg/mgLOQ 20 fg/mgULOL 500 fg/mgImprecision < 13.5%Bias < 13.8%Stable

THCA Validation Results

1000 fg = 1 pg1000 pg = 1 ng

What is a Femtogram

THCA Low

Control

The Collection of Specimen

 

NIAAA – 1 R44 AA016463-02 (Phase II)

UW- Milwaukee- CABHRDe-identified Remnants

POSITIVITY RATETHCA HAIR/NAIL

MEAN CONCENTRATIONSTHCA HAIR/NAIL

Paired Sample t-TestDifference 1449.2 +/- 745.3t = 1.944, df = 59, P < 0.05

60 Matched Pairs of Hair and Nail

0

2000

4000

6000

8000

10000

12000

14000

0 500 1000 1500 2000 2500

Nail T

HC

A (

fg/m

g)

Hair THCA (fg/mg)

r = 0.974

LIMITATIONS

Accurate self-report

Verified dose administration

Demographics

Prevalence not generalizable

Personal hygiene

Cosmetic treatment

Published Results

CONCLUSION

Method is very sensitive & robust

Nail is a suitable alternative

[THCA] hair/nail strongly associated

Slightly higher positivity rate in nail

[THCA] up to 5x higher

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