Question 1

How far back can a hair follicle drug test detect drug use?

Accepted Answer

Hair follicle drug tests can typically detect drug use for approximately 90 days prior to testing. This extended detection window is possible because hair grows about half an inch per month, and the standard 1.5-inch sample represents about three months of hair growth. This makes it significantly more comprehensive than urine tests, which typically detect use within only a few days to a week.

Question 2

Can hair treatments or products affect my test results?

Accepted Answer

Normal hair care products like shampoos, conditioners, and styling products generally do not affect hair drug test results. However, extensive chemical treatments like bleaching, perming, or frequent coloring may potentially reduce drug concentrations in hair. The laboratory washes hair samples before testing to remove external contaminants, focusing on substances that are incorporated within the hair shaft during growth.

Question 3

What happens if I don't have enough head hair for testing?

Accepted Answer

If sufficient head hair is not available, body hair from areas such as arms, legs, chest, or underarms can be collected instead. Body hair grows more slowly than head hair, so it may provide a detection window longer than 90 days. However, the exact timeframe for body hair detection has not been definitively established and can vary between individuals.

Question 4

How accurate are hair follicle drug tests compared to urine tests?

Accepted Answer

Hair follicle drug tests are highly accurate and often considered more reliable than urine tests for detecting habitual drug use patterns. Studies have shown that hair testing can detect four to eight times as many drug users as urine testing. The two-step testing process with initial screening and confirmatory testing helps ensure accuracy and minimize false positives.

Question 5

Can secondhand exposure to drugs cause a positive hair test result?

Accepted Answer

Passive or secondhand exposure to drugs is unlikely to cause a positive result on a hair follicle test. The established cutoff levels and laboratory washing procedures are designed to minimize the chance of environmental contamination affecting results. However, extremely heavy environmental exposure in rare circumstances could potentially affect results, which is why confirmatory testing is performed on all positive screens.

5-Panel Hair Drug Test