FAQs: Multidrug-Resistant Organism & Clostridioides difficile Infection (MDRO & CDI)

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Numerator Reporting for LabID Events: Definition of CDI Assay

Q1: When reporting CDI LabID, what lab result should be reported as an event?For NHSN reporting purposes, a CDI LabID event is a positive laboratory test result for C. difficile toxin A and/or toxin B OR any detection of toxin-producing C. difficile organisms by culture or other laboratory means on an unformed stool specimen that conforms to the container. Testing methods include, but are not limited to, molecular assays such as PCR and/or toxin assays such as EIA.

If a multi-step testing algorithm is used to test for C. difficile toxins, refer to FAQ #2 below.

Antigen results are NOT used to identify a LabID event. The antigen result can be positive or negative but won’t determine if a LabID event is reported. Only toxin results are eligible to define a CD LabID event.

Numerator Reporting for LabID Events: Testing for CDI

Q2: Our facility uses a multi-step process to test for C. difficile toxins, should we report an event if the screening test is positive and the confirmatory test is negative or the opposite (screening test is negative and confirmatory test is positive)?Regardless of the method or sequence of testing, when testing the same unformed stool specimen, the result of the last** test** performed is used to determine if the CDI Laboratory Assay definition is met and a LabID event is submitted to NHSN.   Examples of different algorithms and interpretations for event reporting are provided in the MDRO protocol:  MDRO protocol [PDF – 2 MB].

Only when the final report has specific test times attached to each of the individual testing methods (for example, antigen/toxin and PCR) can one make a valid determination of which test is performed first and which is performed last. If there are no specific test times/time stamps attached to each individual testing method on the final lab report, consider the tests as performed simultaneously and any positive toxin finding is eligible for use.

Numerator Reporting for LabID Events: Acceptable specimens for CDI reporting

Q3: Are specimens collected from colostomy bags considered acceptable for C. difficile LabID event reporting?NHSN doesn’t specify collection methods; Any unformed stool specimen testing positive for C. difficile toxin A and/or toxin B is eligible for use in meeting the definition of CDI laboratory assay. Reporting should be done irrespective of method of collection (for example, stools collected from ostomies), and/or there being a change from the normal consistency or amount of the stool.  These reporting instructions align with the intent of LabID Event Reporting to decrease the burden for gathering information beyond the specimen collection date and admission date and will remove subjectivity and simplify interpretation of the GI-CDI infection criteria.  Specimens labeled something other than ‘stool’ are not eligible for use.

Denominator Reporting for LabID Events: Standard Testing Method for CDI

Q4: Our facility uses a combination of test methods for C. difficile LabID event reporting, how should we answer the question: For this quarter, what is the standard testing method for C. difficile used most often by your facility's laboratory or the outside laboratory where your facility's testing is performed?The response should reflect the testing method used routinely for CDI testing. The response to the question is to be completed in the last month of each calendar-year quarter (March, June, September, and December).  If you change test method during the quarter, select the testing method used for the majority of the quarter.

Numerator Reporting for LabID Event: Transfer rule

Q5: Does the transfer rule apply to the patient at the time of discharge for FacWideIN?The transfer rule does not apply to LabID Event reporting. LabID Events are attributed to the location of the patient at the time of specimen collection. The location of attribution for LabID Events is based on the inpatient location of the patient at time of specimen collection regardless of time spent or procedures performed in the location. There is one special case scenario available for use:  If a specimen collected in an affiliated outpatient clinic (does not include emergency departments or 24-hour observations units included in FacWideIN reporting) is positive for an MDRO or CDI, and the patient it is collected from is admitted to the facility on the SAME calendar date into an inpatient location that is monitoring LabID Events for the identified MDRO or CDI, the positive specimen can be reported as the first specimen for the patient in that admitting inpatient location for the month. If the facility is also monitoring outpatient LabID Events for the same MDRO or CDI in affiliated outpatient clinics (FacWideOUT), then the same specimen for the patient would also be reported a second time for that outpatient location.

Numerator Reporting for LabID Event: Discharged in past 4 weeks

Q6: Why is the question, “Has the patient been discharged from your facility in the last 4 weeks?” required for answer?The question is used to define a C. difficile LabID Event as community-onset healthcare facility-associated (CO-HCFA) (community onset event collected from a patient who was discharged from the same facility ≤4 weeks prior to the current date of stool specimen collection). The question refers to prior discharge from the same facility after an inpatient stay and offers meaningful information for appropriate event categorization. Discharge from an outpatient location (also known as an encounter) such as emergency department and 24-hour observation unit are not eligible for use.

Numerator Reporting for LabID Event: Prior evidence of infection

Q7: Why will the system not let me answer “Yes” to the question “Documented evidence of previous infection or colonization with this specific organism type from a previously reported LabID Event in any prior month?”This is a non-editable data field and will auto-fill by the system based whether a MDRO LabID Event was submitted for the same MDRO and same patient in a prior month (not the current month) at this reporting facility. If there is a previous LabID event for this organism type identified by NHSN in a prior month, the system will auto-populate with a “YES.”  Note:  This data field is NOT used in the calculation of SIRs.

Instructions for completion of the LabID Event form: http://www.cdc.gov/nhsn/forms/instr/57_128.pdf

Numerator Reporting for LabID Event: Admission date for inpatient rehabilitation facilities (IRF)

Q8: What admission and discharge date should be entered when the patient is admitted into an IRF that is located inside of an acute care hospital (ACH)?For NHSN purposes, if the IRF is located inside of the ACH:

• Movement between the ACH and the IRF location is considered a location transfer and is treated as a single facility continuous stay (one admission and discharge).
• The facility admission date for a LabID event should reflect the date the patient was physically admitted into either the inpatient location for the acute care hospital or the IRF location**, **whichever comes first during that patient’s stay.

Numerator Reporting for LabID Event: MRSA bacteremia, all specimen source

Q9: Based on the lab standard our facility follows, sensitivity testing is not required for the same organism if tested within previous 72 hours. Are we required to report a repeat MRSA bacteremia if a result in that timeframe comes back “refer to previous susceptibility.” Do we assume the specimen is MRSA if we do not have sensitivity on that specific isolate?NHSN doesn’t encourage assumptions; the lab report must identify the isolate as ‘MRSA’ [or some form of the name] or be reported with   a susceptibility pattern which meets the definition to qualify for event reporting. MRSA includes S. aureus cultured from any specimen that tests oxacillin-resistant, cefoxitin-resistant, or methicillin-resistant by standard susceptibility testing methods, or any laboratory finding of MRSA (includes but not limited to PCR or other molecular based detection methods).

Distinguishing healthcare-associated infection (HAI) and LabID events

Q10: How does determining a HAI GI-CDI case differ from a CDI LabID event?These are two very different CDI event reporting methods that are each governed by different sets of rules and date timeframes.

CDI LabID Event Reporting is based strictly on the number of hospital days between the specimen collection date and the date the patient is admitted to the facility.  Facility admission date is considered Day 1. There is no consideration for clinical presentation.

• ≤ 3 days = community-onset (CO)
• ≤ 3 days but patient had prior discharge from the reporting facility in the previous 4 weeks = community-onset healthcare facility-associated (CO-HCFA)
• ≥ 4 days = healthcare facility-onset (HO)

GI-CDI HAI surveillance is based on specific infection criteria that are met within the HAI timeframe**:**

• Day of admission or the day after = present on admission (POA) Hospital Day 3 or greater = HAI

Each method requires a positive test for toxin-producing C. difficile on an unformed stool specimen.

Note: Although diarrhea is not a specific element for a GI-CDI event, it must be checked when entering the GI-CDI event to validate that testing was performed on the appropriate specimen type.

Denominator Reporting for LabID Events: Outpatient encounter

Q11: What is the definition of an encounter?NHSN defines an encounter as a patient visit to an outpatient location (ED, 24-hour observation) and is independent of admission to the inpatient facility.  Each encounter must be included in the total encounter count regardless of admission to the facility. Instructions for completion of denominator data for Infection Surveillance and/or LabID Events: http://www.cdc.gov/nhsn/forms/instr/57_127.pdf [PDF – 317 KB]

Denominator Reporting for LabID Event: Facility count

Q12: What is the difference between Total Facility Counts (admissions and patient days) reported on Line 1 and the counts (patient days and admissions) on Line 2 and Line 3?Total Facility Patient Days/Admissions include all inpatient locations in the facility including units with separate CCNs such as inpatient rehabilitation facility (IRF) and inpatient psychiatric facility (IPF) locations.

Line 2 records the total facility counts minus counts from CMS-certified inpatient rehabilitation units (IRFs) and inpatient psychiatric units (IPFs) with** a unique **CCN. This is not a count of patients with an MDRO.

Line 3 records the total facility counts minus counts from CMS-certified inpatient rehabilitation units (IRFs) and inpatient psychiatric units (IPFs) with a unique CCN, and minus counts from all baby locations**.****  **This is not a count of patients with CDI.

NOTE: Patient Days/Admissions on Line 2 and Line 3 of the FacWideIN form refer to the total number of patients housed in eligible inpatient locations (FACWIDEIN) in your facility, regardless of the patient’s MDRO or C. difficile infection status.

Step-by-step instructions for completing this information can be found in the Instructions for Completion of MDRO and CDI Prevention Process and Outcome Measures Monthly Monitoring form (CDC 57.127) [PDF – 61 KB].

Denominator Reporting for LabID Event: Report No Events

Q13: Why do I get an Alert to check the ‘Report No Events’ box on the FacWideIN summary form when I know my facility reported at least one LabID event for this month and location?The ‘Report No Events’ box on the facility-wide inpatient (FacWideIN) form should be checked if there were no LabID events reported in any inpatient location, not including units with separate CCNs. If applicable, the ‘Report No Events’ box must be checked separately for each individual location, that is for, FacWideIN, emergency departments, 24-hour observation units, units with separate CCNs (such as an IRF), and other locations the facility has provided summary data.  For example, all LabID events for the month occur in the ED; you should check the ‘Report No Events’ box on the FacWideIN summary to indicate no inpatient events were submitted for the month.  Review events for each reporting month to determine in which location a LabID event was reported. Check the ‘Report No Events’ box as needed on the appropriate summary forms to complete reporting requirements.

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