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faint line on a drug test

Faint Line on a Drug Test – What Does It Mean?

A common question from our customers – I have a faint line on a drug test – what does it mean? Have I passed or failed the drug test?

How Urine Drug Tests Kits Work

Urine drug test kits are an inexpensive and reliable way of screening for the use of drugs of abuse. They are simple to use and can detect if drugs are present in a person’s urine. Each drug test has a detection level which is the cut-off point that tells us if a drug tests is positive or negative. The drug test cut-off levels will be different for each type of drug. Two of the most widely used urine tests are cannabis drug testing kits and cocaine drug testing kits. A cocaine drug test, for example, has a cut-off level of 300 ng/mL, whilst cannabis has a detection level of 50 ng/mL.

An important point to remember with these types of tests is that they do not tell us how much of a drug is present in a person’s body, they only tell us if the person is above or below the detection level.

Faint Line on a Drug Test – What Does It Mean?

The intensity of the line on a drug test result is not an indication of how much of a drug is present in that person. The intensity of the colour of that line is not important. A line that is only faint is still a line and a faint line in the “T” area of the drug test indicates that the result of the test is negative.

As can be seen in the photo of a negative test shown above, the COC strip is a faint line on a drug test that is much lighter in colour than the other test strip, however the test result is still negative.

Variations in colour intensity are normal for lateral flow drug tests that are based on urine and saliva and should not be a cause for concern. Because of the nature of the physiological liquids being tested, it is not uncommon for the colour intensity to vary. This can be true even for the same person testing at different times on the same day.

The more experienced you become in taking these types of tests, the more you will learn to understand that these changes are to be expected. The most important thing is that the test results are interpreted within the manufacturer’s specified read time to determine the positive / negative result.

Questions about a faint line on a drug test are one of the most common ones we receive. Manufacturers of the tests have also confirmed that the intensity of the line colour on the test is not important. The presence of a line in the “T” region on the drug test, whether it be very dark or very light, means that the test is negative.


Photo by Zoom Testing

Zoom Testing is a leading UK drug testing company and a supplier of Drug Test Kits.

This post was originally published in January 2015 and has been updated since.


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