---
title: "False Positives Guide"
description: "Explore the False Positives Guide near you with AMH Nationwide, offering 20,000+ collection sites and certified MRO review. Call us now at (877) 731-6362."
author: "AMH Nationwide"
date: "2025-08-22"
tags: ["false positives guide"]
canonical: "https://amhnationwide.com/false-positives-guide/"
last_updated: "2026-08-27"
---

# False Positives Guide

**By AMH Nationwide** | August 22, 2025

Explore the False Positives Guide near you with AMH Nationwide, offering 20,000+ collection sites and certified MRO review. Call us now at (877) 731-6362.

---

**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](http://amhnationwide.com/1-year-hair-drug-test/), [nail](https://amhnationwide.com/18-panel-fingernail-drug-test/), [blood](https://amhnationwide.com/5-panel-blood-drug-screen/)

### **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](https://amhnationwide.com/etg-and-peth/) 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

**How AMH Nationwide Helps Prevent and Resolve Testing Errors**

- 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

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**Need a drug, alcohol, HIV or STD test?**

AMH Nationwide is a national lab testing agency operating since 2004, with more than 20,000 collection sites across the United States. Hair, urine, fingernail and blood testing, panels from 5 through 19, for individuals and employers.

- Call: (877) 731-6377
- Find a collection site: https://amhnationwide.com/locations/

- Full page: https://amhnationwide.com/false-positives-guide/