Development of application protocols of the Emit® II Plus 6-Acetylmorphine Assay on the ADVIA® 1800 and 2400 Chemistry Systems.

New application protocols for the Emit(®) II Plus 6-Acetylmorphine Assay for human urine screening have been developed on the ADVIA(®) 1800 and 2400 Chemistry Systems. Precision was evaluated at the cutoff and ±25% controls. Recovery and linearity were studied by spiking 6-acetylmorphine (6-AM) into human urine pools. Method comparison was evaluated using urine specimens and the results were compared to those obtained from the predicate Analyzer (V-Twin(®)). Cross-reactivity with structurally related drugs was assessed at high cross-reactant concentrations. Potential interferences were assessed in the presence of 7.5 and 12.5 ng/mL of 6-AM. The qualitative repeatability coefficients of variation (CV's) ranged from 0.40 to 0.90% and the within-lab CV's ranged from 1.3 to 3.5%. In analyte units (ng/mL), the repeatability CV's ranged from 1.9 to 4.3% and the within-lab CV's ranged from 3.7 to 6.1%. The limit of detection of the assay was found to be 2.5 ng/mL on both instruments. Recovery was within 20% of expected value. Linearity was 2.5-20 ng/mL. Method comparison showed 100% agreement with the predicate analyzer. The assay had minimal cross-reactivity to structurally related opioids including with morphine, morphine-3-glucuronide, morphine-6-glucuronide. No interference was observed with endogenous interferences.

Cefoxitin disk diffusion screen for confirmation of oxacillin-resistant Staphylococcus aureus isolates and utility in the clinical laboratory.

One hundred Vitek-2 identified oxacillin resistant S. aureus (ORSA) isolates were tested by oxacillin screen-plate (OXA-plate) and cefoxitin disk (FOX-disk) for confirmation of oxacillin resistance. Ninety-five of 100 confirmed oxacillin resistant by both, 3 of 5 were oxacillin susceptible by both and mecA negative, and 2 of 5 were oxacillin susceptible by OXA-plate, resistant by FOX-disk and mecA positive. The FOX-disk out-performed the OXA-plate for ORSA confirmation and can be performed using standard laboratory techniques.