Ghost line vs faint line
We get many questions about faint lines. Although there is no single factor which leads to faint test lines, the following are examples of possible causes.
1. “Matrix” interference: Urine is a complex biological specimen. The composition of urine specimens from person to person can vary widely depending on health, fluid consumption, and medication intake of the donor. Likewise, the composition of urine specimens from an individual donor may vary depending on the time of day and other factors. As a result of this inherent variation, the possibility exists that any donor may yield a urine specimen with a composition that produces faint test lines on certain immunoassays. As a result of this possible root cause, it is important to remember that a “line is a line” regardless of how faint and, the presence of a test line within the time limit of the test indicates a negative result for that assay.
2. Cross-Reactivity: We live in an era of unprecedented use of prescription and over-the-counter medications. Although they may not produce the same effect in the body, some medications are chemically similar to the drugs detected in a rapid drug screen test. If a compound is similar enough in structure to the drug being tested, it is possible that the presence of that compound could lead to faint test lines or even a false positive drug screen result. This phenomenon is one of the primary reasons why presumptive positive drug screen test results should be confirmed by an alternate methodology.
3. Assay-to-assay differences: In drug testing, it’s common practice to screen for multiple drugs simultaneously. In the most sophisticated products, as many as 12 drugs can be identified by a single drug screen device. Because of this, it’s easy to forget that each individual assay (even an individual test line on a multi-drug strip) is a separate diagnostic test with unique characteristics. For instance, some rapid drug assays are naturally lighter in line intensity than others. Most often, the light-line phenomenon is seen in THC metabolite tests although drug-class assays such as Benzodiazepines or Tricyclic Antidepressants can also be affected. As with the “matrix effect,” as a result of this possible root cause for light test lines, it is important to remember that a “line is a line” regardless of how faint and, the presence of a test line within the time limit of the test indicates a negative result for that assay.
4. Trace levels of drug in the specimen: It is possible that a faint test line on a rapid drug screen test is the result of the presence of “some” of the drug in the urine specimen (particularly in the case of THC). If this is the case, it is still critically important to note that the concentration of the drug is very likely below the cutoff level of the test, which indicates a negative result. Given the number of other factors which could cause faint test lines, it’s best to not over-interpret light test lines as containing some drug and just remember that the presence of a test line indicates a negative result for that drug.
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How to read Urine Drug Test Results
Urine drug test strips are a popular and inexpensive way to screen for the use of drugs. These easy to use tests determine if a certain level of drugs, also known as the detection level, are present in someone’s urine. The test does not tell you how much or how little of the drug is present , but only if it is above the detection level for the test.
Faint Line on Drug Test – what does it mean?
The intensity of the color of a line on the drug test does not mean anything and should not be interpreted as a measure of the amount of drugs. A faint line on a drug test is still a line, so if you have a faint line in the “T” area of the test then you have a negative drug screen. As you can see in the negative test results photos below, the THC strip is much lighter in color than the OXY test strip, but the test result is still negative.
One of the most common questions we receive is about the faint lines on a drug test and we have confirmed this answer with the manufacturer of the tests – the intensity of the color of the line does not mean anything on the test. Any line in the “T” region of the test strip, dark or very light, is considered a negative test.
How to read iCup Drug Test
The Control Region (C) line must appear at the top of each testing window. The results are read for each numbered line below the (C) line and the number corresponds to the drug letters printed below the window. Below are two examples, one with a 13 panel iCup with all negative results and the other showing a positive result for Opiates and Marijuana.
NEGATIVE Drug Test Results
Two lines of any color intensity appear. A colored line appears in the Control Region (C) and a colored line appears in the Test Region (T).
Even if the line that appears is faint, the result should be considered negative. The possible shades of colored lines in the T Region may vary.
What does a Negative Drug Test result mean? Negative means that the concentrations in the urine sample are below the designated cut-off levels for a particular drug tested. A negative drug test result does not always mean there are no drugs present in the person being tested, it means there are not drugs present above the cut off limit. For example, the cutoff level for marijuana is 50 ng/mL, therefore a person with only 30 ng/mL of THC in their system would test negative on a marijuana drug test. The cutoff levels are suggested by SAMHSA and used to prevent too many false positives for traces amounts of a drug in someone’s system. The cutoff levels are different for each drug and most workplace drug testing use a standard set of cutoff levels. However, law enforcement and addiction treatment programs will sometimes use a lower cutoff level in their testing since they have a zero tolerance policy. If you are using a home drug test, you will want to make sure the cut off level of the test you are using is the same as the one you will be taking elsewhere. Please check your instructions for more information on the cut-off levels being used in your test.
One Line appears in the Control Region (C) and NO line appears in the Test Region (T).
Positive means that the drug concentration in the urine sample is greater than the designated cut-off level for a specific drug and additional confirmatory drug testing may be needed. Please check your instructions for more information on the cut-off levels being used in your test.
What is an INVALID test result?
No line appears in the Control Region (C).
The most likely reasons for this are insufficient specimen volume, incorrect procedural techniques or a faulty test. Please read the directions again and repeat the test with a new test card. If result is still invalid, please contact Home Health Testing at 1-888-448-5657.
How to read a urine drug test result with photo examples of the tests. Answers to your questions about a faint line on a drug test and what it means.