Twelve urine samples were collected, with specific gravities (SG) ranging from 1.000 to 1.035, determined by
a refractometer. Target drugs were spiked into these urine samples at concentrations 50% above and below
the cut-off. The findings indicate that variations in urinary specific gravity do not impact the test results.
The pH of a negative urine pool was adjusted to a pH range of 4 to 9 in 1 pH unit increments and spiked
with Fentanyl to concentrations of 0.5 ng/mL and 1.5 ng/mL. The pH-adjusted urine samples were then
tested with the GenaCheck™ Fentanyl Urine Test Cassette (OTC/CLIA WAIVED) in duplicate. The results
showed that variations in pH across this range did not interfere with the test’s performance.
