Last updated : May 12, 2025
Discovering ways to “beat” a drug test has been on the minds of people who use drugs since drug testing began. Some of their methods could truly be described as “madness,” as a matter of fact. However, technology continues to evolve within the industry, making it nearly impossible for anyone to tamper with the results. For instance, a little-known factor called specific gravity can dash a cheater’s hope of flying under the radar.
Urine drug tests are still the most commonly used employee drug test to detect the presence of drugs in a person’s system. These tests work by analyzing a sample of urine for the presence of certain drug metabolites. Someone who recently used drugs may try to mask them if they know they are about to be tested. The trained eye of the lab techs can raise red flags upon sight. This, coupled with the increased sophistication of lab equipment, makes it very unlikely that someone will successfully “get over” on the company drug test.
Should they attempt it by ingesting a lot of liquid before the test, for instance, specific gravity is a way of measuring how concentrated a urine sample is compared to pure water. It’s calculated by dividing the density of the urine by the density of water. This number provides important information about the urine sample, such as whether it is too diluted or too concentrated.
The difference between high and low
In short, a low specific gravity means the urine is diluted. So, of course, that means a high specific gravity signifies concentrated urine. The concentration of urine is influenced by various factors.
They are:
- Fluid intake
- Dehydration
- Kidney function
The specific gravity of urine is critical in the context of urine drug testing. It affects the concentration of drug metabolites in the sample.
Drug metabolites are the byproducts of drug metabolism that are eliminated from the body through urine. The concentration of drug metabolites in urine can vary depending on various factors such as the dose, route of administration, frequency of use, and individual metabolism.
However, one critical factor affecting the concentration of drug metabolites in urine is the specific gravity of the sample. If urine is diluted, drug metabolites will be more diluted which makes them more difficult to detect in the sample. On the other hand, if the urine is concentrated, the concentration of drug metabolites can be higher, making it easier to detect them during the drug test.
As a result, urine with low specific gravity may sometimes result in false-negative drug test results as small amounts of drug metabolites may not be detectable. A urine sample with a high specific gravity could result in a false-positive drug test result. In other words, it could indicate drug use even when the person isn’t under the influence of any drug.
Cut-off levels are the deciding factor
The trigger for conducting the specific gravity test during a drug test analysis is whether or not the creatinine level in the urine sample is off-kilter. Creatinine is a waste product that the body produces from normal wear and tear on the muscles. It’s the result of the breakdown of creatine, an amino acid.
The levels fluctuate depending on such things as age, race, gender, and body size. A low creatinine level indicates that urine is diluted. It’s a red flag that goes up immediately during a drug test analysis. The normal range is between 20 and 400 milligrams per deciliter (mg/dL). If the creatinine level is between 2 and 20 mg/dL, the urine is diluted.
Testing facilities use the specific gravity measurement of urine samples to interpret the results. Urine samples with a specific gravity of less than 1.003 or higher than 1.033 are considered adulterated. The test is marked inconclusive due to that possibility. This is because such specific gravity measurements indicate that the sample is either too diluted or too concentrated, which can significantly affect the accuracy of drug test results.
Giving the benefit of the doubt
Just because a urine analysis proves to be diluted, it doesn’t necessarily indicate that the person was trying to mask drug use. Some people intentionally drink lots of water to stay healthy. Others—especially if they suffer from shy bladder syndrome—may have been trying to fill their bladder hoping they can give a urine sample when requested to do so. Lastly, we’ll note that certain medications or specific kidney problems cause urine dilution.
Employers often provide some tips for employees to follow before a drug test. They can prevent your workers from obtaining an inconclusive result because the specimen was diluted.
They are, as follows:
- Limit fluid intake before the test
- Avoid diuretics, like coffee and tea, for example, before the test
- Report for the test early in the morning
If your employees require frequent hydration throughout the day, as in the construction industry, for instance, consider collecting the urine sample before having them report to work.
The specific gravity of urine is a critical factor affecting the accuracy of urine drug test results. Testing facilities adhere to strict specific gravity cutoff values because it ensures that the results of the test are accurate and reliable.
Should an employee receive an inconclusive result related to specific gravity, follow the procedure outlined in your drug-free policy specifically from that point forward. It helps ensure you have proper evidence should a disgruntled employee try to drag you into court down the road.
