Modern drug tests can detect synthetic urine, often called “fake urine,” due to sophisticated screening protocols. Synthetic urine is a manufactured liquid designed to chemically and physically mimic human urine, containing substances like urea, creatinine, and salts. However, laboratories have developed specific testing procedures to identify samples that have been substituted or altered. These advanced testing methods make it substantially more difficult for a synthetic product to pass as a legitimate biological sample. Drug testing facilities now employ a multi-step verification process to ensure the integrity of every specimen submitted for analysis.
The Purpose of Specimen Validity Testing
Laboratories utilize a two-part process for drug screening: first, checking authenticity, then testing for prohibited substances. Specimen Validity Testing (SVT) is the dedicated procedure used to detect substitution, dilution, or adulteration of a urine sample. This process is a built-in quality control measure that confirms the specimen is consistent with normal human urine.
SVT is necessary because a substituted or adulterated sample can lead to a false negative result, potentially compromising the accuracy of the drug test. Validity testing occurs simultaneously with the initial drug screen to ensure that only a confirmed human urine sample proceeds to the drug analysis.
Initial Detection: Temperature and Appearance
The first form of validity testing occurs immediately at the collection site and involves physical checks. A crucial indicator is the sample’s temperature, which must fall within the narrow physiological range of 90°F and 100°F (32°C to 38°C) to be considered authentic.
The temperature is measured immediately after collection using a strip attached to the cup. If the sample falls outside this specified range, it is flagged as suspicious and may be rejected. Personnel also visually inspect the specimen for unusual color, excessive foam, or foreign materials, which can instantly flag the sample for further scrutiny.
Chemical Verification: Markers of Authenticity
The primary defense against synthetic urine is the laboratory’s chemical analysis, which checks for specific biomarkers of human biology. Synthetic urine often fails because it cannot perfectly replicate the complex chemical profile of a biological sample. The laboratory tests for three main parameters: creatinine, specific gravity, and pH level.
Creatinine is a waste product of muscle metabolism that is consistently present in human urine. A valid sample must contain a minimum concentration, typically 20 milligrams per deciliter (mg/dL). Levels below 2.0 mg/dL are considered substituted and physiologically impossible for human urine. Levels between 2.0 and 20 mg/dL may indicate a highly diluted sample.
Specific gravity measures the density of the sample, reflecting the concentration of dissolved solids like salts and waste products. Normal human urine has a specific gravity range, generally from 1.005 to 1.030. A reading outside this range may indicate the sample was diluted with water or substituted with a liquid lacking the proper density.
The pH level, which measures acidity or alkalinity, is also scrutinized. Human urine normally falls within a pH range of approximately 4.5 to 8.0. Samples that are extremely acidic (below 3.0) or alkaline (above 11.0) are flagged as adulterated because these values are inconsistent with human physiology. Laboratories also test for oxidizing agents, such as nitrites or bleach, which are sometimes added in an attempt to destroy drug metabolites.
Outcomes of a Failed Validity Test
When a urine specimen fails any part of the Specimen Validity Testing, it is reported with a specific result that indicates the nature of the failure. The three main classifications are “Substituted,” “Adulterated,” or “Invalid.” A substituted result means the sample is not consistent with human urine, which is the classification typically given to synthetic urine.
An adulterated result means a substance was added to the sample after it was collected, often to mask drug use. An invalid result is given when the lab cannot obtain a scientifically supportable result due to interference, but the cause cannot be definitively determined. For employment or legal testing, a verified substituted or adulterated result is generally treated as a refusal to test, which is often considered the same as a positive drug test under organizational policy.