VITEK MS Collaborative Study Outline - eBook

Proceed likewise for a second sample, etc.  1  After about five minutes check for crystal formation on the spots. Inexperienced users may find using a  2  magnifying glass helpful. Measurement will succeed only if matrix crystals have become visible as a  3  yellowish film. Ideally, most of the spot’s surface will be coated with crystals. 

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6  When the VITEK MS‐DS target slides have been prepared, they must be tested within 48 hours.  7  Prepared slides should be stored at room temperature until they are tested.  10  The preparation of yeast samples differed from the standard procedure in that VITEK MS‐FA (formic acid  11  treatment) was applied to the organism on the VITEK MS‐DS prior to adding VITEK MS‐CHCA. Care was  12  taken not to add VITEK MS‐CHCA until the VITEK MS‐FA was completely dry, usually after 1 ‐ 3 minutes.  13  The sample was applied to the VITEK MS‐DS as in the standard procedure. Then 0.5 μl of VITEK MS‐FA  14  was added to the sample, using a new pipette tip for each sample. Enough time was allowed for  15  evaporation of VITEK MS‐FA before adding VITEK MS‐CHCA. The cell suspension formed a thin, moist  16  film on the target position. This usually took between 1 ‐ 3 minutes. Once the slide was completely dry,  17  1.0 μl of the VITEK MS‐CHCA was added to each sample as in the standard procedure.  18  Follow VITEK MS package insert instructions for running the instrument.  19  Note: The E. coli calibrator was not treated with VITEK MS‐FA.  20  8  9  Sample Preparation for Yeast 

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Interpretation and Test Result Report  23  The VITEK MS system identified blind‐coded organisms (previously characterized) by comparing the  24  characteristics of the obtained spectrum to the VITEK MS knowledge base. A percent agreement  25  calculation was performed.  26  A quantitative value, the confidence value, was calculated and expressed the similarity between the  27

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