• Diluted Sample – This is actual urine from the donor that has been diluted either by drinking excessive amounts of water (water loading) before voiding or by adding water directly to the sample after voiding, in an effort to reduce the concentration of drug metabolites in it. The problem with diluted samples these days is that they will never get past the screening stage. Many instant urine drug test kits have built-in validity checks.

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• Temperature Test – Adding water to a sample lowers its natural temperature and it will immediately be flagged for possible tampering.

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• Color – Diluting with water also changes the natural light from golden yellow color of urine to something unnaturally pale or almost colorless, and this observation will be noted down on the Chain of Custody Form (CCF).

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• Odor – Urine has a natural ammonia odor and an experienced and well-trained drug testing technician will be able to tell the difference between a completely odorless sample and an unadulterated sample.

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• Specific Gravity-Normal specific gravity for urine should be in the range of 1.003 to 1.03. A high specific gravity indicates a high amount of solid materials in the urine (urine is more concentrated). A low specific gravity (lower than 1.003) indicates a diluted specimen.

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• Creatinine – Creatinine is a byproduct of muscle metabolism and appears in urine in relatively uniform amounts over the course of each day. It is used as an indicator of whether a specimen is actually urine and how much water it contains. A creatinine level between 2mg/dL and 10mg/dL is indicative of short-term water loading, a common practice when people try to dilute their urine so that any drugs contained therein will be diluted below cut-off levels for analytical testing. Anything lower than 2mg/dL means the sample is not human urine.

 

• Enhanced Sample – An enhanced (adulterated) urine sample is one to which a structure-altering agent is added in order to mask the presence of drugs enough to decrease its concentration that it doesn’t show in a test. Urine pH levels outside the normal range of 4.5 to 9 may be an indication of tampering, and this will be noted in the CCF. However, it is worth mentioning that poor handling/storage conditions like elevated temperatures can cause the urine pH level to reach up to 9.5. Common adulterants include soap, bleach, salt and eye drops.

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• Substituted Sample – Synthetic urine is big business these days. Many who go in for their drug tests submit fake urine, or real human urine from another person who’s clean. People have been known to submit apple juice or animal urine, which can both be easily flagged by a standard specimen validity test like pH and creatinine tests respectively.