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False Positives Guide

Understanding False Positives in Hair, Nail, and Blood Drug Testing: A Complete Guide to Causes, Accuracy, and Next Steps

Why False Positives Matter

• Define what a false positive is in drug testing
• Real-life implications: employment, legal cases, custody, rehab programs
• Mention of testing methods offered by AMH Nationwide: hair, nail, blood

False Positives in SCRAM Monitors

SCRAM (Secure Continuous Remote Alcohol Monitoring) ankle devices are commonly used in court-ordered programs to detect alcohol use through transdermal testing. However, false positives can occur — sometimes caused by environmental exposure to alcohol-based products, device calibration issues, or even certain medical conditions. If you believe you’ve received a false positive SCRAM monitor or false positive SCRAM ankle monitor result, time is critical. Call AMH Nationwide immediately to arrange a hair, nail, or PEth alcohol test to confirm your sobriety.

Learn more about our ETG & PETH Testing Services →

What Causes False Positive Drug Tests?

• Medications that trigger false positives (e.g., antihistamines, antidepressants, antibiotics, CBD)
• Passive exposure to substances (e.g., secondhand marijuana smoke, fentanyl dust)
• Contamination from cosmetic or hygiene products
• Sample handling issues and lab error

False Positives by Test Type: Hair, Nail, and Blood

Hair Testing

• External exposure (e.g., smoke, drug powder)
• Contamination from hair products or bleaching

Nail Testing

• Environmental contact, long detection window
• Rare but possible false positives if nail absorbs substances through cuticle or nail bed

Blood Testing

• Highly accurate but sensitive to trace levels
• False positives may result from recent prescriptions or metabolic overlap

Confirmatory Testing: Your Safety Net

• Screening test vs confirmatory test (immunoassay vs GC-MS or LC-MS)
• How confirmatory testing reduces false positives
• Importance of lab certification and chain-of-custody documentation

What to Do After a False Positive Drug Test

Steps:

1. Request a copy of your test results
2. Review recent prescriptions and supplements
3. Request confirmatory testing (e.g., GC-MS or LC-MS)
4. Submit documentation of medications to the lab
5. Contact your HR department, attorney, or testing company
6. Request a retest if within detection window

False Negatives in Drug Testing: Causes and How to Dispute

What is a False Negative?

• A test result that shows no drugs present, even when substances were used
• Can undermine workplace safety, legal proceedings, or addiction monitoring

Causes of False Negatives:

• Testing done outside the drug’s detection window
• Low dose or infrequent use
• Sample dilution or tampering
• Outdated or limited panel not detecting synthetic drugs
• Sample degradation or lab error

What to Do:

• Request a broader or more sensitive test panel
• Consider switching to a different sample type (e.g., nail or hair)
• Retest within appropriate window
• Use certified labs with high sensitivity thresholds

• Multi-step testing: initial screen + confirmatory test
• CLIA-certified labs with strict chain-of-custody
• Offers retesting and expert guidance for disputed results
• Tests available: 4 panel up to 19 panel, or alcohol testing by etg or peth

Conclusion & Call to Action

• Recap key takeaways: false positives and false negatives are both fixable
• Choose experienced, certified providers to avoid misclassification
• Contact AMH Nationwide for accurate drug testing, retesting, or case review