FAQs: Miscellaneous

Yes. The repeat infection timeframe (RIT) is set by the date of event (DOE).  For surveillance purposes a POA infection may only have a DOE on the day of admission to an inpatient location or the next day. If the first element within the infection window period (IWP) occurred in the 2 days before admission, the DOE is considered the day of admission to an inpatient location. The RIT is the 14-day timeframe where no new infections of the same type are reported, beginning with the date of event. 

Example: A symptomatic UTI (SUTI) with E. coli identified with DOE on the day of admission is considered POA. If 10 days later a new SUTI with K. pneumonia is identified, then the K. pneumonia is added to the original UTI. The UTI RIT remains Hospital Days 1-14. 

NOTE:  If a patient is admitted with a POA BSI and subsequent blood specimens are collected, the POA BSI must be identified as either primary or secondary in nature.  A primary POA BSI will set a BSI RIT.  However, a POA BSI that is secondary to another site of infection will NOT set a BSI RIT.  It will only set an RIT for the type of infection to which the BSI is secondary.  

For infections of all types except VAE, PedVAE, SSI, LabID Event, to make a proper determination regarding a possible healthcare-associated infection, proceed in this order:  

1. First, determine the date of the diagnostic test that is an element of the NHSN site-specific infection criterion that is met.  
2. Next determine the infection window period (3 days before the diagnostic test, the day of the test, and 3 days after for a total of 7 days).  NOTE: when the diagnostic test used to set the IWP is hospital day 3 or earlier, the days before the diagnostic test can only include those that occur in the POA timeframe, specifically the 2 days prior to admission.  
3. Then determine if all of the elements of the criterion are met during the infection window period.  If they are, there is an infection event.  If they are not, there is no event.   
4. If there is an event, next determine the date of event, specifically, the date that the first element used to meet the infection criterion occurs for the first time within the infection window period.   
5. Is the date of event in the POA timeframe (specifically, during the 2 days before admission, the day of admission, or the next day)?  If yes, the infection is POA; if not, it is an HAI. Please note, when assigning a repeat infection timeframe (RIT) for a POA event, if the date of event is determined to be either of the two days prior to inpatient admission then the date of event, and therefore day 1 of the RIT, is considered hospital day 1.

Chapter 2 of the NHSN PSC Manual – Identifying HAI for NHSN Surveillance provides guidance and examples.  Please see:
http://www.cdc.gov/nhsn/PDFs/pscManual/2PSC_IdentifyingHAIs_NHSNcurrent.pdf 

Surveillance definitions are designed to study and identify trends in a population.  The application of these standardized criteria, and only these criteria, in a consistent manner allows confidence in aggregation and analysis of data. Alternatively, clinical diagnoses are patient specific. Unlike surveillance definitions, ALL available diagnostic data are considered in a clinical diagnosis, including additional clinical, epidemiological, and laboratory data not used for NHSN surveillance. Therefore, a clinical diagnosis may be made even when a surveillance definition may not be met or vice versa Failure to meet a surveillance definition should never impede or override clinical judgment during diagnosis, management, or treatment of patents. Nor should failure to meet clinical definitions result in non-reporting to NHSN infections meeting the NHSN surveillance criteria. 

The following are considered diagnostic tests only when they are an element of the criteria that is met: 

• Laboratory specimen collection 

• Imaging test    

• Procedure or exam 

This term refers to the identification of microorganisms using a method of testing other than a traditional culture. Culture based testing requires inoculation of a specimen to culture media, incubation, and observation for actual growth of microorganisms. Depending on the organism identified, culturing can take several days to weeks for a final report. In contrast, non-culture-based testing (NCT) methods generally provide faster results, which can assist with early diagnosis and tailoring of antimicrobial therapy. Examples of non-culture-based testing include, but are not limited to, PCR (polymerase chain reaction) and ELISA (Enzyme-linked immunosorbent assay) as well as DNA sequencing. NCT is defined as a methodology that identifies an organism directly from a specimen without inoculation of the specimen to any culture media. For instance, NCT does not include identification by PCR of an organism grown on any other culture media prior to performing PCR testing. 
 

For purposes of NHSN surveillance, Active Surveillance Culture/Testing (ASC/AST) refers to testing that is intended to identify the presence/carriage of microorganisms for the purpose of instituting or discontinuing isolation precautions or monitoring for eradication of a carrier state. ASC/AST does NOT include identification of microorganisms with cultures or tests performed for diagnosis and treatment purposes (for example, specimens collected from sterile body sites, including blood specimens).  Common examples of ASC/AST include nasal swabs for detection of MRSA and rectal swabs for detection of VRE or C. difficile.  

A positive screening culture at admission will not meet an NHSN infection criteria. If the patient meets an NHSN surveillance definition on or after HD 3, an HAI is reported.  

The CCN does not define NHSN enrollment. Facilities located in physically separate locations should be enrolled individually in NHSN with a unique NHSN identifier (NHSN orgID).  If there are several different buildings on the same campus but physically connected (underground tunnel, connecting corridors etc.) and all buildings are a part of the same facility, only a single NHSN identifier is assigned to cover all buildings. When a CCN is shared across multiple facilities, the CDC will aggregate the data from all applicable NHSN Org IDs and will send data to CMS under the single CCN for CMS reporting purposes. Additionally, each distinct facility’s data is analyzed individually to facilitate HAI monitoring and prevention efforts at the facility level for the purposes of accurate tracking and targeted infection control. 

Because fever is a non-specific sign of infection, it is possible that an individual may run a fever due to more than one infection at a time. It would be impossible to determine which infection (if not both) was the cause of the fever. Therefore, in this example, if all other criteria besides fever are met, the patient would have both an NHSN PNEU and an NHSN UTI. This process negates the use of clinical, subjective decision making to determine NHSN HAI events. 

The issue of the route of temperature measurement was considered here at NHSN and a decision was made to forego requiring a certain route of measurement, since our aim is not to direct care, but rather to measure the effect of care on outcomes.  A detailed literature search was performed, and subject matter experts were consulted regarding the many routes of temperature measurement and what they may mean when compared to others.  The final determination was that there are no research-based guidelines concerning converting temperatures based on route of measurement.  When using fever as an element of an NHSN infection criterion, use the temperature documented in the patient’s medical record (no conversion of temperature based on route of collection). 

If a specific value for a vital sign is not stated in a CDC/NHSN HAI definition criterion (for example, hypotension), the facility should use the vital sign parameters as stated in its own policies and procedures for clinical practices.  Additionally, documentation of these conditions in the medical chart may also be used, for example, “…patient is hypotensive” would satisfy the element of “hypotension.” 

The patient ID is the key identifier in NHSN for each facility. Therefore, the patient ID should be an identifier that remains constant for the patient on any subsequent visits; oftentimes, this is the medical record number. The use of an identifier that changes with each visit to the facility, for example, would result in the inability to link an SSI to a procedure, as well as inappropriate assignment and calculation of LabID events and subsequent measures. 

Yes, all patients housed in an inpatient location are included in HAI surveillance, denominator data collection, and LabID event surveillance for the inpatient location.  The facility’s designation of a patient as ‘observation, swing bed, or hospice’ will not exclude them from standard surveillance activities for the unit. 

Only if physician diagnosis is a part of an NHSN site-specific infection criterion may it be used in the determination that an infection was present on admission (POA). For example, since the BSI criteria do not include physician diagnosis as part of the criteria, a physician documentation of BSI cannot be used to meet CDC/NHSN criteria for a BSI.  As a reminder, the date of event of a CDC/NHSN site-specific infection criterion must occur within the POA timeframe (specifically the 2 days before admission, the day of admission, or the day after admission) for the infection to be considered present on admission. This is regardless of admitting diagnosis or treatments the patient may be receiving upon admission (for example, antibiotics). 

NHSN takes documentation at face value and of equal value; any evidence of infection documented in the patient record is eligible for use with NHSN criteria. For example, if there is documented purulence on HD 4 and ‘no purulence noted’ documented HD 5, the HD 4 documentation is eligible for use with infection criteria.  The subsequent documentation doesn’t cancel out/negate using the first documentation.  NHSN can’t adjudicate differences in documentation or differences in labeling of cultures.  If there is a discrepancy in culture collection and culture label, it is left to the facility to clarify conflicting documentation and decide which documentation reflects findings accurately.

If a device is present for any part of a calendar day, then that day contributes to the minimum day requirement for the device-associated infection. Examples include when a device is removed and then reinserted on that calendar day or the next.  If instead, a full calendar day passes (not to be read as 24 hours) without device presence, then the day count begins anew for device days if the device is reinserted. An example is the removal of a device on Monday, without reinsertion until Wednesday or later. 

Denominator data are collected at the same time, every day, per location.  Alternatively, a denominator sampling method can be used where the number of patients in the location (patient days) and the number of patients with an indwelling device (urinary catheter/central line/ventilator) is collected on a designated day each week at the same time.  For accuracy, do not use Saturday or Sunday for sampling purposes and only non-oncology ICUs and wards with an average of 75 or more device days per month in the previous year are eligible to use this method.  When using this method, the patient days must also be counted each day of the week.   

Positive cultures from broth only are considered a positive culture result and treated as such for surveillance purposes.  Such media can be enriched to identify organisms that might otherwise be missed. 

Please see NHSN’s Requirements and Recommendations on usage: https://www.cdc.gov/nhsn/faqs/faq_general.html 

For NHSN surveillance purposes, an imaging finding of ‘free fluid’ is not definitive or equivocal for an NHSN infection criterion – it is considered a negative imaging finding. A ‘fluid collection’ imaging finding could be indicative of infection (such as an abscess or early formation of an abscess) and therefore is considered an equivocal imaging finding and eligible to cite an NHSN site-specific infection if clinical correlation is also present.  Clinical correlation is physician documentation of antimicrobial treatment for the site-specific infection related to equivocal findings (not clearly identified) of infection on imaging test. 

Up to three pathogens may be reported. If multiple pathogens are identified, enter the pathogen judged to be the most important cause of infection as #1, the next most as #2, and the least as #3 (usually this order is indicated on the laboratory report). If the species is not given on the lab report or is not found on the NHSN terminology browser drop down list, then select the genus only.  (Report all site-specific pathogens before secondary BSI pathogens).  It is not possible to include every organism on the NHSN organism list, therefore, it is possible for your laboratory to identify an organism that cannot be found when referencing the NHSN Organism List. DO NOT assume that such an organism is not eligible for a CLABSI event but instead, contact NHSN via ServiceNow. Access ServiceNow at https://servicedesk.cdc.gov/nhsncsp. If you do not have a SAMS login, or are unable to access ServiceNow, you can still email the NHSN Help Desk at [email protected]. 

The COVID-19 question is required for all HAI events and is intended to gather data on HAIs related to the COVID-19 condition. To reduce subjectivity, the lab finding of the most recent COVID-19 viral test prior to or on the date of event (HAI) should be used for the response.   

• Answer COVID-19 as ‘YES’ if the patient is lab test confirmed COVID-19 prior to or on the date of event (HAI).  Keep in mind that patients may undergo repeat testing post-treatment and may move from a ‘confirmed’ to ‘negative’ COVID-19 status. 

• Answer COVID-19 as ‘NO’ if the most recent lab test prior to or on the date of event (HAI) is negative.
   

We did not include in our definition a length of time for the patient to be considered ‘confirmed’; however, we focus strictly on the current hospitalization and the response should be based on the lab test available within the current patient record.   

It is our hope that the data received over time will enable us to identify the risk of the COVID-19 condition on HAIs. 

“With no other recognized cause” means the sign/symptom is eligible for use in meeting the NHSN infection criteria unless there is physician documentation within the medical record that specifically states the sign/symptom is due to a condition other than the one under investigation. The determination to exclude a sign/symptom with no other recognized cause must be made by the local facility based on the documentation available in the medical record.