1. describe plan for data analysis for demographic variables (descriptive statistical tests). 2. describe plan for data analysis of study variables (descriptive and inferential statistical tests)

Extraneous Variables

Extraneous variables are unexpected variables that can affect the outcome and validity of a research study. Choosing an appropriate method to measure the research variables is an extremely important step in the research process (Grove, Burns, & Gray, 2013). Regarding this research study, the potential for extraneous variables include compliance with isolation precautions; compliance with timely specimen collection; laboratory handling and processing techniques; timeliness of preemptive isolation initiation; patient case index; and staff competency in completing the assessment screening tool properly. The research team will work closely with the hospital infection prevention department to strengthen compliance with infection control protocols. Members of the research team will also conduct bi-weekly rounding to ensure appropriate isolation precautions are in place. The registered nurses who will be conducting the initial patient assessments and specimen collection with be thoroughly educated on the use of the assessment tool, the proper technique to collect the rectal swab specimen, and the importance of prompt initiation of isolation precautions if indicated. This will be done via webinars and live in-services. All specimens will be processed in the on -site certified laboratory by a trained technician. Further laboratory related variables will be controlled by the choice of instrument which features internal and external controls, as well as functions to decrease cross-contamination. These functions will be discussed further in the proceeding text.

Instrument Selection

The first instrument that is necessary for the proposed study is an on-demand polymerase chain reaction (PCR) test, more specifically, the Xpert Carba-R assay. The Xpert Carba-R Assay performed on the GeneXpert Instrument Systems is a diagnostic test for the detection and differentiation of multiple gene sequences associated with CRE. The results of the assay are automatically generated after they are interpreted by the GeneXpert instrument system software from measured fluorescent signals and embedded calculation algorithms. Basic users will see the results displayed as “detected” or “not detected”. (Moore, Canton, Carretto, Peterson, Sautter, & Traczewski, 2017). The choice to use this instrument is based on previous research which has shown molecular techniques to yield higher sensitivity and specificity in comparison to culture-based approaches. Molecular techniques are also more favorable due to rapid turnaround times. The Expert Carba-R assay, which is manufactured by Cepheid solutions, is the first FDA-cleared assay that can detect five families of carbapenemase genes directly from rectal swab specimens. The reproducibility of the Xpert Carba-R Assay was previously established in a multi-center study which found that 1836 of the 1847 samples successfully produced the expected result on the first attempt. In addition, research involving 633 rectal swabs found that the Xpert Carba-R had a sensitivity of 96.6% and specificity of 96.6% (Richter, & Marchaim, 2017). The use of the Xpert Carba-R assay reduces laboratory error due to the  systems use of disposable cartridges that are self- contained, reducing cross-contamination. In addition, it also features built-in quality control mechanisms. One being the sample processing control (SPC) which ensures adequate processing of the target bacteria and to indicate the presence of inhibitors in the PCR reaction. The SPC also ensures that the PCR reaction temperature and time are appropriate for the amplification reaction and that the PCR reagents are functional. The probe check control (PCC), which is an internal feature, verifies reagent rehydration, PCR tube filling in the cartridge, probe integrity, and dye stability (Cepheid, 2016). This instrument will identify the presence or absence of CRE, this is considered a ratio level of measurement.  A ratio scale is appropriate for this study. The ratio level of measurement will allow for the comparison of infection rates before and after the intervention period (Gray, Grove, & Sutherland, 2017).

The other instrument that will be used in this study is a CRE carriage assessment screening tool. The screening algorithm will be utilized by the registered nurses on every patient upon admission. The assessment tool is designed to assist the nurses in identifying high-risk patients who meet the inclusion criteria.  The tool consists of the following questions: 

• Does the patient have a history of antimicrobial therapy within 90 days?
• Is the patient being admitted from a long term care facility or a LTACH?
• Was the patient previously hospitalized within the last 90 days?
• Does the patient have an invasive line?
• Is the patient on a mechanic