Drug testing is a common practice in various environments, including pre-employment screenings, ongoing employment, sports, and legal settings. These tests serve to detect specific substances or their byproducts in biological samples, most frequently urine. Understanding test outcomes, especially ambiguous results, is important for both individuals and organizations.
What “Negative Dilute” Means
A “negative dilute” drug test result indicates no detectable levels of target drugs or their metabolites were found, but the urine sample was less concentrated than expected. The “negative” part confirms the absence of detected substances above cutoff levels. The “dilute” part refers to the specimen’s concentration, assessed by measuring creatinine levels and specific gravity.
Creatinine is a waste product from muscle metabolism, usually present in urine at a consistent concentration. In a diluted sample, creatinine levels are lower than the established threshold, often below 20 mg/dL. Specific gravity measures urine density compared to water, indicating its concentration. A specific gravity below typical ranges, such as less than 1.003, suggests a dilute specimen. These low values indicate higher water content, which can affect test reliability.
Reasons for a Dilute Sample
Several factors can lead to a dilute urine sample, many being physiological rather than intentional. A common cause is increased fluid intake, such as drinking large amounts of water or other beverages before the test. This can be due to regular hydration habits or an attempt to provide a sufficient sample.
Recent urination can also contribute to a dilute sample, as the urine has had less time to concentrate in the bladder. Certain medications, particularly diuretics (often called “water pills”), increase urine production and can result in a diluted specimen. Medical conditions affecting kidney function can also lead to consistently diluted urine.
Consequences and Retesting
A “negative dilute” result is not a failed drug test, but it often triggers a retest. The diluted sample makes it difficult to definitively confirm the absence of substances, as a highly diluted sample might mask drug presence. Therefore, employers and organizations frequently require a new sample.
Policies for negative dilute results vary among organizations. Some employers accept the result as negative, while others mandate a retest, sometimes under direct observation. For example, Department of Transportation (DOT) regulations may require an observed retest. Adhering to retest instructions is important, as declining a retest is often treated as a refusal to test, carrying the same consequences as a confirmed positive result.