Hair Drug Testing in Charlotte

How Hair Drug Testing Works

Drug metabolites enter the bloodstream after use and are deposited into the hair shaft as it grows. Because hair grows approximately 1.5 inches every 90 days, a 1.5-inch sample collected close to the scalp reflects roughly the past three months of potential drug use. That growth pattern is what creates the extended detection window.

During collection, a trained collector cuts a small sample from close to the scalp, seals it, and documents the chain of custody before sending it to a certified laboratory. The sample comes from the hair strand itself, not the follicle beneath the skin. That distinction matters for integrity: it can’t be diluted, substituted, or adulterated at the collection site the way a urine sample can. If head hair is insufficient, body hair may be used as an alternative, though because body hair grows more slowly than scalp hair, the detection window may extend beyond the standard 90 days rather than reflecting a precise three-month period.

What Hair Drug Testing Detects

Standard hair drug testing screens for marijuana and THC, cocaine, opiates and opioids, amphetamines and methamphetamines, and PCP. Expanded panels may screen for additional substances depending on the purpose of the test.

One important limitation: hair testing doesn’t capture use that occurred within approximately five to ten days of collection, since newly consumed drugs haven’t yet been incorporated into visible hair growth. For situations requiring detection of very recent use, urine testing offers higher precision for that narrow window.

Hair vs. Urine Drug Testing

Choosing between hair and urine testing comes down to what you need to know and how far back you need to see it.

• Detection window: Hair testing looks back up to 90 days; urine testing typically covers one to seven days
• Tamper resistance: Hair samples can’t be diluted or substituted at the collection site; urine tests are more vulnerable to adulterant-based tampering
• Recent use: Urine testing is more accurate for use within the past several days
• Cost: Urine testing is generally less expensive
• Best use cases: Hair testing fits employers with strict drug-free workplace policies and legal situations requiring long-term documentation; urine testing is common for post-accident and reasonable-suspicion scenarios

Preparing for Your Hair Drug Test

Preparation is straightforward. Hair should be clean and free of heavy styling products on the day of collection. No fasting or dietary changes are needed.

Let the collector know about any medications or supplements you’re taking, as these can sometimes affect results. If your hair has been heavily chemically processed, mention that at check-in. Visibly damaged hair may be flagged by the laboratory. Our certified collectors are glad to answer any preparation questions before or during your appointment.