1. A negative result in the test device for Barbiturates may not necessarily indicate Barbiturates-free urine. Explain why. 2. If adulteration is suspected, the test should be repeated using a new...

Extracted text: 1. A negative result in the test device for Barbiturates may not necessarily indicate Barbiturates-free urine. Explain why. 2. If adulteration is suspected, the test should be repeated using a new urine specimen. What are examples of adulterants which would interfere with test results for Barbiturates detection in urine? 3. Two subsequent urine test devices for Barbiturates were interpreted as invalid. Both test devices came from same lot. What would be the next best course of action for the clinical laboratory scientist?