SPECIMEN VALIDITY TESTING

Specimen Validity Testing (SVT) also referred to as adulteration testing, is the test method employed to determine if a urine specimen is abnormal or has been tampered with. The DrugCheck tests can include color reactive tests strips to aid in this analysis. There are key factors that can be used to make this screening determination:

pH

Normal urine range from 6.0 to 7.0, but can vary from 4.5 to 8.0. High pH urines can be seen in UTIs or from diets high in vegetables and diary products. Low pH urines result from uremia, severe diarrhea, starvation and diets high in ascorbic acid or citric fruits.

Specific Gravity (SG)

Measures urine concentration, or the amount of dissolved substances present in urine compared to distilled water. Normal range is from 1.002 to 1.030. High values are caused by dehydration, glycosuria, and radio-opaque dyes. Low values occur in diabetes insipidus, renal disease and diuretic use.

Creatinine (CR)

Waste product from creatine metabolism that originates from skeletal muscles. Creatinine is excreted in the urine at a constant rate. Normal range: 20 mg/dl to 200 mg/dl. pH Normal urine range from 6.0 to 7.0, but can vary from 4.5 to 8.0. High pH urines can be seen in UTIs or from diets high in vegetables and diary products. Low pH urines result from uremia, severe diarrhea, starvation and diets high in ascorbic acid or citric fruits.

Nitrite (NI)

Present in the urine from urinary bacterial infections with levels at 0.1 mg/dL to 5 mg/dL. The cutoff for adulterated samples is >15 mg/dL. The presence of bleach will give an abnormal result.

Oxidants (OX)

Tests for the presence of oxidants, such as bleach and peroxide, in the urine. Oxidants, when present in urine, will produce a blue or green color.

GLUTARALDEHYDE (GL)

Test for the presence of an aldehyde. Adulterants such as UrinAid and Clear Choice contain glutaraldehyde which may cause false negative screening results by disrupting the enzyme used in some immunoassay tests. Glutaraldehyde is not normally found in urine so its detection is generally an indicator of adulteration.

Some common substances used by donors to try and adulter a specimen are as follows: