Urine Specimen Validity Testing

Dilute Specimen - A urine specimen with creatinine and specific gravity values that are lower than expected for human urine.

A urine specimen from a single specimen collection or the primary (Bottle A) specimen from a split specimen collection is reported dilute when the initial or confirmatory tests have creatinine and specific gravity results of:

(i) The creatinine concentration is less than 20 mg/dL;

(ii) The specific gravity is less than 1.003; and

(iii) The creatinine and specific gravity results do not meet the criteria for a substituted or invalid result.

Substituted Specimen - A urine specimen with creatinine and specific gravity values that are so diminished or incongruent that they are not consistent with normal human urine.

A urine specimen from a single specimen collection or the primary (Bottle A) specimen from a split specimen collection is reported substituted when the creatinine test and specific gravity test have the following results:

(i) The creatinine concentration is less than 2 mg/dL; and

(ii) The specific gravity is less than or equal to 1.001 or greater than or equal to 1.020.

Adulterated Specimen - A urine specimen containing a substance that is not a normal constituent or containing an endogenous substance at a concentration that is not a normal physiological concentration.

A urine specimen from a single specimen collection or the primary (Bottle A) specimen from a split specimen collection is reported adulterated when:

(i) The nitrite concentration is confirmed to be greater than or equal to 500 mcg/mL;

(ii) The pH is less than 3 or greater than or equal to 11;

(iii) The specimen contains an exogenous substance (i.e., a substance which is not a normal constituent of urine); or

(iv) The specimen contains an endogenous substance at a concentration greater than what is considered a normal physiological concentration.