Creatinine Levels and Spec. Gravity Confirmation

[TheLevityInThis]

Does anyone know how a typical drug screening clinic works as far as confirmation test?

Does the sample have to fail both creatine and spec gravity to be considered dilute?

Or is it still considered dilute, even if it fails just one of the confirmation test?

Thanks Guys!

[Burnt Toast]

Both the creatinine and SG must be below satisfactory numbers in order to be ruled diluted. Samples are ruled "substituted" when the creatinine and SG levels are so low and/or divergent that its not consistent with human urine.

Refractometry is used as the confirmatory methodology for SG, while Colorimetry is used for creatinine. Details of both methodologies and more, can be found here:
http://www.workplace.samhsa.gov/DrugTesting/pdf/Analytical%20Testing%20Methods%20-%20February%202005.pdf