NHSN Definition and Rules Changes for January 2016

Author: Centers for Disease Control and Prevention (CDC)

Welcome to the 2016 National Healthcare Safety Network Quick Learn series. These CDC presentations are an educational resource for healthcare facilities working to prevent Healthcare Associated Infections, or H-A-Is. In this session, we’ll review definition changes to the National Healthcare Safety Network, or NHSN, patient safety component for 2016. CDC reviews and makes changes to NHSN infection definitions for several reasons.Definitions are sometimes updated in response to user feedback and to remain current with diagnostic practices. NHSN strives to be receptive and responsive to concerns from those who apply the definitions. If a definition needs to be changed, NHSN works to ensure data elements comprising the definition can be collected, that the change is objective and can be applied consistently, and that it’s based on published scientific findings. For 2016, there are fewer changes than last year.

Some changes affect multiple NHSN modules. The other changes affect the definitions of bloodstream infection, or B-S-I, intra-abdominal infection, and pneumonia. Here are the changes that affect more than one NHSN surveillance module: First, newer, non-culture based diagnostic laboratory testing that provides specific organism identification is used more frequently in patient care settings. As a result, NHSN accepts these tests for many of the 2016 infection definitions. One example is a polymerase chain reaction, or PCR test, which identifies organisms present in patient specimens. A blood specimen with Klebsiella pneumonia identified by PCR could be used to meet the laboratory confirmed bloodstream infection, or LCBI, criteria.

Second, there are some new pathogen exclusions for 2016 infection definitions and protocols. Some fungal pathogens, rarely implicated in H-A-Is, are excluded from the NHSN organism list. Excluded genera are limited to Blastomyces, Histoplasma, Coccidioides, Paracoccidioides, Cryptococcus, and Pneumocystis. Finally, results of laboratory tests performed on specimens collected from patients after they have been documented as brain dead and being supported for organ donation purposes can no longer be used to meet any NHSN infection definitions. The following changes are specific to BSI surveillance. NHSN is removing Salmonella organisms as BSI pathogens.

It is highly unlikely that Salmonella organisms would cause a primary bloodstream infection. For that reason, these organisms are excluded as primary BSI pathogens. The next change is that there are two exceptions in which a patient may meet the CLABSI definition, but not have a CLABSI reported. The first exception involves patients whose medical record contains documentation that the patient was observed or suspected of injecting into their own intravascular lines during the LCBI infection window period, or IWP. This behavior must be documented in the patient’s medical record and the documentation must occur during the three days before, the day of, or the three days after the positive blood culture collection. The second exception is a patient who has a central line, but who also has an infected noncentral-line vascular access site, OR has an infected central line site which was not accessed during the hospitalization. In this case there must be BOTH an organism identified in a blood specimen, AND purulence from the access site which tests positive for at least one matching organism in the blood. The pus from the access site must be collected during the LCBI IWP.

NHSN Definition and Rules Changes for January 2016

In both exceptions, if a facility reports the BSI to NHSN, the data field central line should be marked No. If additional blood tests are positive for organisms after the BSI repeat infection timeframe additional documentation would be necessary to exclude the BSI as a CLABSI on the same grounds. In 2016, an additional criterion is added to intra-abdominal infection, or I-A-B, criteria.

If a patient has an abscess or other evidence of I-A-B on gross anatomic or histo-pathologic exam and an organism from the list included here is identified in the blood, the patient meets the criterion for I-A-B. The list includes organisms belonging to the following genera: Bacteroides, Candida, Clostridium, Enterococcus, Fusobacterium, Peptostreptococcus, Prevotella, Veillonella, and organisms from the Enterobacteriaceae family. If this I-A-B is not a surgical site infection, the elements must occur within the IWP. Also, the culture or microbiologic testing must be performed for purposes of clinical diagnosis or treatment and not active surveillance. An example is when a patient is taken to the operating room and an intra-abdominal infection is identified.

The infection is documented in the medical record, but no cultures are collected from the intra-abdominal space and blood specimens test positive for Enterococcus faecium. In this case, the IAB criterion would be met. The previous NHSN I-A-B criterion 3b, which included two signs or symptoms of infection, plus the identification of organisms from blood and an imaging test evidence of infection, is now modified. The organisms identified in the blood must now contain at least one of the organisms we just identified for the new I-A-B criterion.

These changes provide consistency for the I-A-B criteria while more accurately identifying intraabdominal infections with secondary bloodstream infections. Positive tests from bronchial alveolar lavage or protected specimen brushing procedures are now allowed as elements of the infection criterion for pneumonia, or PNU-3. This is in addition to sputum and endotracheal aspirate tests that identify microorganisms.

Positive tests from these sites are more specific than those from sputum or endotracheal aspirate, and therefore should be interchangeable in the criterion. A matching positive test for Candida species from blood and from one of these sites during the pneumonia infection window period fulfills the laboratory portion of the PNU-3 criterion. For more information about the NHSN protocol and definitions, visit C-D-C-dot-gov-slash-N-H-S-N.

Questions can be e-mailed to N-H-S-N@C-D-C-dot-gov.

NHSN Definition and Rules Changes for January 2016

Welcome to the 2016 National Healthcare Safety Network Quick Learn series. These CDC presentations are an educational resource for healthcare facilities working to prevent Healthcare…

By: Centers for Disease Control and Prevention (CDC)