Usually, a drug test will come back with a clear positive or negative result, but sometimes an inconclusive drug test result is recorded. What does this mean, and what happens when your drug test result is inconclusive?
What Is An Inconclusive Drug Test Result?
What does inconclusive mean on a drug test? It is recorded when the drug testing laboratory can’t categorize your result as positive or negative.
Drug testing is a scientific procedure and lab technicians need to be precise in their methods and confident in the result they report. They won’t make a guess.
What Causes A Drug Test To Be Inconclusive?
A drug test can be inconclusive for several reasons:
- Improper collection methods
- Break in the chain of custody
- Improper storage
- Faulty testing
- Sample adulteration
Which Types Of Drug Test Can Be Inconclusive?
All types of drug tests can be inconclusive if there’s a problem with the sample collection, delivery, storage, or testing procedures.
But only saliva or urine testing is susceptible to adulteration, and urine samples are the most commonly adulterated type of sample.
A saliva sample could be adulterated by substances that change the pH of saliva, or by substances that produce excessive salivation and cause sample dilution.
Urine samples can be diluted by drinking large amounts of water before the sample collection.
Blood tests and hair follicle tests can’t be tampered with, and these tests would only produce an inconclusive drug test result if there was a problem with the sample collection or testing procedure.
What Happens When A Drug Test Is Inconclusive?
Your employer should have a clear process in their drug testing policy that details what will happen when a drug test result is inconclusive.
If you’re taking a pre-employment drug test, an employer may ask you to take another test, or they may pass you over.
If you’re already employed, your employer will usually ask you to take another test. You shouldn’t face any disciplinary action because of an inconclusive result. Your employer could have raised suspicions about you, however.
For employees working in safety-sensitive positions, you may be asked to take an observed drug test depending on the reason for the inconclusive result.
An observed drug test means that you’ll be watched while you provide your urine sample to ensure that you don’t tamper with the sample.
Depending on your employer’s policy, you may not be allowed to carry out your normal duties until you receive a negative result from your second drug test.
Should your second drug test come back with an inconclusive result, your employer may conclude that you’ve deliberately tried to cheat the test.
How Is A Urine Sample Tested At The Lab?
When the lab receives your urine sample, the paperwork is checked to ensure that the chain of custody is intact.
Urine samples go through several phases of testing and your urine sample will undergo an adulteration check as part of the testing process.
Urine Adulteration Check
The adulteration check looks for substances that shouldn’t be present in urine and also measures the specific gravity and the creatinine level of your sample to determine if your urine has been diluted.
Creatinine is checked first. Normal urine has a creatinine level above 20 mg/dl.
Some medical conditions like kidney disease, muscle wasting, and diabetes can result in abnormal creatinine levels, so labs don’t rely on creatinine levels alone to check for urine dilution.
If your sample has a lower creatinine level than normal, then the specific gravity will be checked.
The specific gravity of urine should be between 1.005 and 1.030. A lower specific gravity shows that urine has been diluted.
Immunoassay Urine Test
The immunoassay test is used to give an initial result. Samples that are negative for drugs on this test aren’t tested further unless the sample showed dilution or adulteration.
An immunoassay test uses antibodies. If drugs are present in the sample, a reaction will occur and the sample will then undergo further testing to confirm drugs in the sample and determine the exact level.
Gas Chromatography-Mass Spectrometry (GC/MS) Testing
This testing method identifies drug molecules in a sample and will determine the level of any drugs present.
Knowing the exact level of a drug in a sample is important because a sample will only be recorded as positive if the quantity of the drug is at or above the cutoff level. When a drug is present in an amount below the cutoff level, then the test is negative.
Cutoff Levels Used In Urine Drug Testing
Different cutoff levels are used for the initial immunoassay drug test and the confirmatory GC/MS analysis. In the list below, the first number is the cutoff level for the initial test, and the second number is the cutoff level for the confirmatory test. For some drugs, the cutoff levels are the same for both tests.
- Marijuana 50 ng/ml – 15 ng/ml
- Cocaine 150 ng/ml – 100 ng/ml
- Codeine/Morphine 2000 ng/ml – 2000 ng/ml
- Hydrocodone/Hydromorphone 300 ng/ml – 100 ng/ml
- Oxycodone/Oxymorphone 100 ng/ml – 100 ng/ml
- Phencyclidine 25 ng/ml – 25 ng/ml
- Amphetamine/Methamphetamine 500 ng/ml – 250 ng/ml
- MDMA/MDA 500 ng/ml – 250 ng/ml
- 6-Acetylmorphine (Heroin) 10 ng/ml – 10 ng/ml
How To Make A Drug Test Come Out Inconclusive
If you’re taking a saliva test, you may be able to produce an inconclusive result by altering the pH of your saliva by sucking on sour candy.
However, saliva tests include a 10-minute waiting period before the sample collection, where you aren’t allowed to eat or drink anything. During that waiting period, your saliva pH could return to normal.
If you’re taking a urine drug test, a diluted sample may produce an inconclusive result, but there’s no guarantee.
Drug testing methods are a lot more advanced than they used to be, and the lab could record the result as inconclusive or they could record the result as a positive dilute or a negative dilute.
- A positive dilute means that drugs were detected in the urine sample, and the urine sample contained a high concentration of water.
- A negative dilute means that no drugs were detected in the sample and the sample contained a high concentration of water.
Positive-dilute results are treated the same as positive results.
Negative dilute results require a second drug test and it’s this result that will give you those crucial extra days to detox during the period between giving your first and second samples.
However, you should know that there’s no way you can be certain that you’ll get an inconclusive or negative-dilute result.
How to Make A Drug Test Come Out Inconclusive? 2 Common Methods
Drinking an excessive amount of water before providing a urine sample is the most common way that people try to dilute urine.
It’s usually sufficient to drink two or three 12 oz (350 ml) glasses of water about 1 hour before you give your urine sample. Don’t go overboard here.
Drinking enormous quantities of water in a short period can lead to water intoxication, which is very dangerous because your electrolyte levels are too low.
Taking diuretic pills is another method that will produce diluted urine, but those pills can have unpleasant side effects and it’s never a good idea to take unnecessary pharmaceuticals.
Although you can try to give a diluted urine sample in an effort to receive an inconclusive or negative-dilute result, the test collection site may have procedures in place to prevent dilute specimens.
The technician at the clinic or collection site will certainly check the temperature of your urine sample to make sure that you didn’t add water to your sample, or use a fake urine product. If a sample isn’t at or close to body temperature, it won’t be accepted and you’ll have to produce another sample.
Some collection sites will also asses the color of your urine and if it’s too light, you’ll be asked to provide another sample. You’ll have to urinate every 15 minutes until you produce an undiluted sample.
Receiving an inconclusive drug test result will usually mean that you’ll have to take another drug test.
If you’re already employed, you won’t face disciplinary action or lose your job because of an inconclusive result.
Trying to force an inconclusive result when you know that you’re going to test positive is a tough trick to pull off, and you may end up with a dilute-positive result instead of an inconclusive result.
When you receive an inconclusive result that requires a retest, the second test will take place quickly, and while two or three extra days could be long enough to detox from some drugs, a few extra days may not be long enough to make a difference for regular marijuana use.
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