FAQs: Bloodstream Infection (BSI) Events

Central Line- Associated Bloodstream Infection and Non-central line-associated Bloodstream Infection

Secondary BSI

Q1: How do I determine if an LCBI is a primary BSI or secondary to another site and therefore not reported as a CLABSI?

If you believe an LCBI is secondary to a non-blood source of infection, you must first fully meet one of the NHSN site-specific infection definitions as defined in Chapter 17 (CDC/NHSN Surveillance Definitions for Specific Types of Infections), or the PNEU, UTI, or SSI protocols. Once you have done this, apply the Appendix B guidelines (Secondary BSI Guide) located in Chapter 4 pdf icon[PDF – 1 MB] of the NHSN Patient Safety Component Manual.

There are only 2 scenarios in which a BSI can be deemed secondary to another site- specific infection for NHSN reporting purposes:

  1. The blood specimen and primary site-specific specimen (used to meet the primary infection criteria) must have at least one matching organism, AND the collection date of the blood specimen is within the primary site-specific infections secondary BSI attribution period. (Scenario #1)


  1. The blood specimen must be an element used to meet the site-specific infection criterion and be collected in the site-specific infection window period (Scenario #2)

The rules for the infection window period and secondary BSI attribution period always apply. More guidance about these rules can be found in Chapter 2 (Identifying HAIs in NHSN) pdf icon[PDF – 1 MB].

Additionally, a BSI may also be secondary to VAE following the guidance outlined in the VAE protocol pdf icon[PDF – 2 MB].

NOTE: If the patient does not meet any of the site-specific infection criteria from PNEU, UTI, SSI, VAE, or any of the definitions in Chapter 17 and does not meet the requirements for secondary BSI, then the LCBI must be reported as a primary LCBI and as a CLABSI if an eligible central line is present on the BSI date of event or the day before.

Site-specific criteria and secondary BSI

Q2: How do I determine which site-specific criteria uses blood as an element in order to potentially meet secondary BSI criteria?

NHSN developed Table B-1 (Secondary BSI Guide) as a reference to assist users in making secondary BSI determinations. The table lists definitions that require a blood specimen with at least one matching organism to the site-specific specimen (Scenario #1) and definitions that use a blood specimen as an element to meet the site-specific definition (Scenario #2). All elements of the site-specific infection definitions must be met before a secondary BSI determination can be made. Table B-1 can be found in Chapter 4 pdf icon[PDF – 1 MB] of the Device Associated Module BSI.

Secondary BSI to lower respiratory events in locations performing VAE surveillance

Q3: How do I identify a secondary BSI for lower respiratory tract events in ventilated patients in adult locations where VAE surveillance is performed?

To determine if a positive blood culture can be attributed as a secondary bloodstream infection (BSI) related to a lower respiratory tract event, consider the following steps:

1) Does the patient meet any of the VAE definitions?

  1. If the PVAP definition is met, then you may attribute the blood culture to the VAE (as a secondary BSI) IF the blood culture meets the various requirements as outlined in the VAE protocol pdf icon[PDF – 1 MB] – the organism isolated from blood must match an organism isolated from the respiratory tract culture used in meeting the PVAP definition AND the blood culture must be collected during the 14-day VAE event period.
  2. If only the VAC or IVAC definition is met, then the positive blood culture CANNOT be secondary to the VAE (as per the VAE surveillance protocol BSIs cannot be deemed secondary to VAC or to IVAC).

2) If the PVAP definition is met, a positive blood culture can either be secondary to the VAE (if it meets the VAE secondary BSI criteria outlined in the protocol and summarized in 1a, above), or secondary to one of the other major HAI sites (specifically, another Chapter 17 definition, PNEU, UTI or SSI definition), or it may be a primary BSI/CLABSI.

3) If only the VAC or IVAC definition is met, or if no VAE definition is met, then the positive blood culture can be evaluated to see if it is secondary to any of the major sites as defined in Chapter 17 or  PNEU, UTI or SSI event protocols. If the patient does not meet one of these other definitions, the BSI may need to be reported as a primary BSI/CLABSI

Secondary BSI assignment to a PNEU event

Q4: What if a blood specimen collection date occurs outside the Infection Window Period of PNU1 or does not match the pathogen used to meet PNU2 or PNU3? Is it possible for a BSI to still be attributed to the PNEU event?

Yes, it is possible.

A secondary BSI cannot be attributed to PNU1. However, in this instance if a BSI is thought to be secondary to pneumonia but the blood culture collection date did not occur within the infection window period such that it could be used as an element to meet the PNU2 definition, reassess to determine if the PNU2 definition can be met within the PNEU RIT. Similarly if PNU2 is met and there is a subsequent blood specimen with an eligible pathogen, however it does not match the specimen used to originally meet PNU2, then reassess to determine if PNU2 can be met using the blood culture such that the date of event falls within the originally established PNEU RIT. NOTE: When re-meeting PNEU within the RIT, a single eligible imaging finding with a test date that occurs in a new IWP and demonstrates evidence of persistence of prior eligible findings will satisfy the imaging requirement for all patients. New or progressive or serial imaging (for patients with underlying cardiac or pulmonary disease) does not have to be re-demonstrated. Evidence of persistence of eligible findings alone will meet the imaging requirement in the RIT. See the example and table below.

All elements necessary to satisfy the PNU1 definition occur within the infection window period. The date of event is 2/14. This establishes a PNEU (PNU1) RIT 2/14- 2/27 and a BSI secondary attribution period 2/11 – 2/27.  Subsequently a blood specimen with a collection date 2/20 identifies Pseudomonas aeruginosa. The collection date is within the secondary BSI attribution period for the PNEU event; however, a secondary BSI cannot be reported for PNU1 since the blood culture is not used to satisfy the PNU1 definition and there is no site-specific culture to which the blood culture pathogen can match. If during the PNEU RIT and within a new IWP, all elements needed to meet the PNU2 definition are present to include the blood specimen and this results in a date of event within the RIT, then the BSI can be attributed as secondary to the PNEU event.  The PNEU date of event remains as 2/14, as does the originally determined RIT, secondary BSI attribution period, device association and location of attribution. If the PNU2 definition is not met as described above and if additionally, another specific site infection for which the BSI can be attributed as a secondary BSI is not identified, then the BSI is a primary BSI/CLABSI.

Table listing Date; repeat infection timeframe, infection window period, and secondary BSI attributable period.

Secondary BSI Assignment to a GIT 1b or IAB 2b when organisms are identified on histopathologic exam.

Q5. How can I deem a blood culture secondary to a GIT 1b or IAB 2b when organisms are identified on histopathologic exam?

To deem a blood culture secondary to GIT 1b or IAB 2b when organisms are identified on histopathologic exam, you must meet the following criteria:

  1. The blood specimen must be an MBI Organism.
  2. The histopathologic evidence element and blood specimen are captured in a GIT or IAB IWP.
  3. The organism identified on the pathology report must match the organism in the blood specimen.  See example below:

2/2: Pathology Report:Classical budding hyphae and spores of Candida admixed with ulcer slough (intestines).  2/4: Blood culture: Candida albicans.  Because the Candida in the blood culture is an MBI Organism, the histopathologic findings and blood specimen are captured in the GIT IWP, and the organism identified in the pathology report and blood specimen match, the Candida blood specimen is deemed secondary to a GIT 1b.

MBI-LCBI vs. secondary BSI

Q6: How do I determine if a positive blood specimen otherwise meeting criteria for a Mucosal Barrier Injury-Laboratory Confirmed Bloodstream Infection (MBI-LCBI) should be reported as secondary to a gastrointestinal infection (GIT) when the patient has symptoms that may be due to their disease process or due to an infectious process (for example, nausea, vomiting, diarrhea, etc.)?

CLABSI surveillance is intended to capture BSIs that are associated with the central line itself.  This association may be due to either suboptimal insertion or maintenance issues.  In such an infection the blood is believed to be the primary site of infection.  The MBI-LCBI criteria was implemented to enable NHSN to identify BSIs that are believed to be the result of the patient’s weakened immune state and the accompanying alterations of the gut.  In such situations, the patient truly has a primary BSI, because there is not an infection at another site.  However, the gut is simply the source of colonizing organisms which seed the bloodstream.  Both situations, where the BSI is primary in nature, are different from those in which the BSI is believed to be secondary to an infection at another site.  An example is a BSI that is secondary to a GIT infection in which the bloodstream becomes a second site of infection through seeding from the original infection site.

The goal of adding MBI-LCBI criteria to CLABSI surveillance is:

  1. To capture MBI-LCBI that occur in the absence of other infections (in other words, primary BSIs) but in the context of non-infectious disturbances such as neutropenia or GVHD
  2. To avoid reporting MBI-LCBIs which are due to another site of infection (in other words, secondary BSIs). This is not always an easy determination.  It will take some clinical judgment, but the aim should be to capture as MBI-LCBIs those BSIs where the patient’s symptoms (nausea, vomiting, diarrhea, etc.) are felt to be due to the GVHD or treatment side effects and NOT due to an infectious process in the gut.  The organisms involved may provide some suggestion in this determination.  When clinical interpretation indicates that there is an infectious process occurring in the gut, AND the patient meets one of the GI infection criteria, AND the guidance in Appendix 1 Secondary BSI Guide is followed, then such BSIs should be considered secondary to another site of infection and not reported as CLABSI.

MBI-LCBI Reporting

Q7: Are MBI-LCBI data removed from the CLABSI data submitted to CMS?

Yes. Effective with the 2015 re-baseline, MBI-LCBIs are no longer included in the CLABSI metrics used for national reporting or in files that are shared with CMS for reimbursement determinations. A separate report has been created for MBI-LCBI tracking. However, NHSN has not changed the requirement for hospitals to include MBI-LCBIs if the locations monthly reporting plan includes CLABSI surveillance. We believe the continued collection and tracking of MBI-LCBI data is important because these infections cause significant morbidity and mortality for patients and through their identification and measurement exists the potential to identify new prevention efforts.

Distinguishing serial reportable infections from single, unresolved infection

Q8a: Does the Repeat Infection Timeframe, (RIT) eliminate the continuation of an infection investigation?

Yes, the creation of the repeat infection timeframe (RIT) eliminated the subjectivity of trying to determine if an infection was on-going or resolved. The 14-day RIT is the period of time in which no new BSIs will be reported. The date of event (DOE) for the primary BSI is day one of the 14-day BSI RIT. Only primary BSIs create a BSI RIT. Secondary BSI’s do not create a BSI RIT but the site-specific infection to which the BSI is secondary does create a 14-day RIT for infections of the same type. If a BSI is identified outside of the 14 day BSI RIT, a new event is identified and must be investigated as being primary or secondary in nature.


Q8b: Example-If a person meets the definition for CLABSI with a positive Staphylococcus aureus culture on hospital day 12 and on hospital day 18 another blood culture is positive with an eligible pathogen, is this a new CLABSI?

In  this example, if a primary BSI with a DOE on hospital day 12 is identified, and another positive blood specimen meeting LCBI criteria is identified with a DOE within the 14 day RIT, no new LCBI will be reported but any additional organisms identified will be added to the initial BSI event. The next possible DOE for a new BSI would be hospital day 26, which is day 15, the day after the 14 day RIT ended. For complete details regarding RIT, please see Chapter 2 pdf icon[PDF – 1 MB].

Note: RITs are only set when an infection criterion is met, and they are specific to the type of infection identified and do not affect reporting of other types of infections. BSIs that are secondary to another primary site of infection do not meet the NHSN LCBI criteria. A secondary BSI to a primary site of infection does not create an RIT of its own that captures all subsequent positive blood cultures. Therefore, subsequent positive blood specimens may need to be investigated to determine if they are primary BSIs and possible CLABSIs.

Event Type

Q9: A patient with no central line in place has a blood specimen collected on hospital day 4 that meets LCBI criteria.  On hospital day 5 a central line is inserted, and another positive blood specimen is collected on hospital day 8 meeting CLABSI criteria.  Do I change the initial event to a CLABSI?

No. Device association, the date of event, and the location of attribution are never changed from the initial determination when subsequent BSI events occur during a BSI RIT. The subsequent positive blood specimen, within the BSI RIT, is considered an extension of the initial BSI event.

Blood culture collection methods

Q10: If two blood specimens are drawn, one through a central line, and one from a venipuncture and the venipuncture specimen is negative for growth but the blood collected from the central line grows an NHSN pathogen, does this meet the CLABSI criteria?

Yes.  The collection site (venipuncture site or central line drawn) of the blood specimen does not determine the eligibility of the positive blood specimen to meet CLABSI criteria. All positive blood specimens, regardless of the sites from which they were collected or the purposes for which they were drawn must be included in CLABSI surveillance. NHSN does not require that a BSI be attributed to a particular device for reporting purposes.  A BSI is determined to be central line associated (CLABSI) if an eligible central line (central line that has first been accessed and has been in place for more than 2 consecutive calendar days) was present on the BSI date of event (DOE) or the day before. The day of device placement is CL Day 1 or if the central line was present on admission (POA), the day of first access in an inpatient location is CL Day 1 for making device-associated attributions.

Defining “separate occasions”

Q11: What does the term “on separate occasions” mean when referring to blood specimens positive for common commensals?

The term “on separate occasions” is required for laboratory-confirmed bloodstream infections (LCBIs) when only common commensals are identified in the blood (LCBI 2 or 3).  Poor blood specimen collection techniques can result in the growth of common commensals due to contamination of the blood specimens.  The requirement for at least 2 blood specimens with matching common commensals collected on separate occasions was implemented to avoid identifying a truly contaminated specimen as an LCBI.  Blood specimens drawn from different sites, at different times, or with different accession numbers should undergo separate decontamination steps (skin prep) thereby decreasing the likelihood of “true” contamination.

  • Think about separate “occasions” as referring to the act of disinfecting the access site; in other words, different venipunctures, a combination of venipuncture and lumen withdrawal, or different lumens of the same central line), or at different times. The intention is to ensure that blood specimens are collected following the performance of two separate site disinfections.
  • Typically, blood culture orders involve collecting 2 sets of cultures which include 2 bottles per set (4 bottles total) with each set drawn from a different site. Having a positive set of cultures (2 positive bottles from the same blood draw) does not meet the separate occasion requirement for common commensal organisms. At least one bottle from each set, collected from different sites or from the same site but after performing 2 site decontamination steps, would have to be positive to meet the “separate occasion” requirement.
  • If both culture sets are positive, there is less chance that contamination was the cause than if 2 positive blood cultures were collected from a single blood draw (in other words, collected using a vacutainer or via venipuncture and attaching multiple bottles after a single decontamination of the site), these specimens would be considered a single access (or the same occasion).

Common Commensals Are Single Element

Q12: Which date should be used for the date of event if two matching common commensal blood cultures collected on consecutive days are the first elements to occur in the IWP meeting LCBI 2 or 3?

The two matching common commensal blood cultures are considered a single element for use in meeting LCBI 2 or 3 criteria.  If signs/symptoms occur within the Infection Window Period (IWP) BEFORE the first collected blood specimen, the date of event (DOE) will be the date the first element (sign/symptom) used to meet LCBI 2 or 3 criteria occurred.  If the sign/symptom occurs AFTER the collection date of the first blood specimen, the date of event (DOE) will be the collection date of the first positive blood specimen that occurred during the infection window period (IWP).

Matching Common Commensals

Q13: A patient had S. capitis in one blood culture and S. auricularis in another collected on consecutive days. Since both specimens are identified to the species level, would it be correct to call these contaminants?

Both S. auricularis and S. capitis are coagulase negative staphylococci (CNS) however, they are identified to the species level, which is different, therefore, they are not considered companion (matching) specimens. Since each organism was identified in a single blood culture, they are both considered contaminants and are disregarded for NHSN reporting purposes. LCBI 2 or 3 criteria are not met because 2 blood cultures, collected on separate occasions, with matching common commensals are not present.

If neither of the specimens had been speciated but instead were reported as coagulase-negative staphylococcus, they would be considered companion (matching) cultures.

NHSN Organism List

Q14: Why have some organisms been moved from one list to another?

The NHSN Organism List undergoes revisions based on current organism taxonomy. The list can be found under the Supporting Material section on any of the NHSN event landing pages (BSI, MDRO/CDIFF, PNEU, SSI, UTI, and VAE).

Annual updates are possible therefore, the appropriate version (published the same year as the BSI event) should be referenced when conducting CLABSI surveillance.

  • 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 email at nhsn@cdc.gov for reporting guidance.

Any organism not found on the NHSN Common Commensal list* is considered a recognized pathogen for NHSN reporting purposes.

*Please note: this does not include the following excluded organisms: Campylobacter, C. difficile, Enteropathogenic E. coli, Listeria spp., Salmonella spp., Shigella spp., and Yersinia spp. and it also does not include organisms that are excluded from meeting any NHSN infection definition: Blastomyces, Histoplasma, Coccidioides, Paracocidioides, Cryptococcus, and Pneumocystis.

Central line counts for device attribution and denominator data

Q15: When a patient is admitted to an inpatient location with a central line in place, and that line is NOT accessed during the hospitalization, are those days included in the  denominator device day count?

Beginning in January 2018, all central lines (permanent, temporary, implanted ports, and umbilical lines) will be treated the same for making device attribution determinations (specifically, CLABSI) and for counting denominator device days (central line days).

  • Denominator data: Central lines that are present on admission should be included in device day counts beginning on the day of admission. This is consistent with the other device associated protocols (CAUTI and VAE) and is intended to simplify the collection of denominator data.

For example, a patient admitted on Jan. 1 with a central line in place that is first accessed on Jan. 4th, has a BSI DOE on Jan 6th. A total of 6 central line days will be entered for the denominator device day count.

  • Device-attribution (CLABSI event): An eligible central line must be present to make a device-associated determination (CLABSI). An eligible central line is a device that has first been accessed in an inpatient location and has been in place for more than 2 consecutive calendar days. “Access” is defined as line placement, or use of the line for infusion, withdrawal of blood or hemodynamic monitoring. Once a line becomes an eligible central line (CL Day 3 after access), it continues to be eligible for a CLABSI event until the line is removed from the body or the patient is discharged, whichever comes first.

For example, a patient admitted on Jan. 1st with a central line in place that is first accessed on Jan. 4th, has a BSI DOE on Jan 6th.  Because the line was first accessed in an inpatient location and it has been in place for more than 2 consecutive calendar days on Jan. 6th, it is eligible for a CLABSI event. If the line is never accessed, it never becomes eligible for a CLABSI event but is included in the denominator device day counts. NOTE: if a patient has another central line in place at the same time that is accessed, device attribution (eligible for a CLABSI event) begins on CL Day 3 after access.

Removal and reinsertion of a central line

Q16: What is considered a calendar day when a central line is removed and later reinserted?

If a central line is present for any part of a calendar day, then that day contributes to the minimum day’s requirement for the CLABSI.  If a full calendar day passes without a central line being present, then the device day count starts over once a new CL is inserted. Please see Table  3 of the NHSN 2020 BSI Protocol pdf icon[PDF – 1 MB] for examples.

Midline catheter

Q17: Does a midline catheter qualify as a central line?

Midline catheters by description are not intended to terminate in one of the great vessels or near the heart which is the definition of a central line. However, the actual location of the catheter tip is the determining factor and the chest x-ray obtained to verify line placement should indicate the location of the tip.   Also, consider the line’s intended use. To qualify as a central line, it must be used for infusion, withdrawal of blood, or hemodynamic monitoring.

Catheter tips

Q18: Why are central line catheter tips not used to meet NHSN LCBI criteria?

Catheter tip cultures are not used for NHSN CLABSI surveillance for several reasons.  Catheter tip cultures have been shown to have higher rates of contamination than blood cultures.  Furthermore, not all laboratories are able to perform quantified catheter tip cultures. Catheter tips are a part of other types of non-NHSN surveillance such as catheter-related BSI (CRBSI) which is generally thought of as a clinical definition, used when diagnosing and treating patients.

The Guidelines for the Prevention of Intravascular Catheter-Related Infections, 2011 pdf icon[PDF – 50 KB] address CRBSI and may be helpful when addressing a physician’s questions.

Multiple central lines

Q19: If a patient has two central lines in at the same time, how do I determine to which line to attribute the positive blood culture?

NHSN does not require a CLABSI to be attributed to a specific central line. Instead, you will simply be required to document whether an eligible central line was present on the BSI date of event or the day before. An eligible central line is a device that has first been accessed in an inpatient location and has been in place for more than 2 consecutive calendar days.

Only 1 central line day is counted per patient-per calendar day regardless of how many lines the patient may have in place at the same time. If a patient in a SCA/Oncology unit has both a temporary and a permanent line, only report the temporary line because it has a higher risk of infection.

Purulent drainage from IV site

Q20: If a patient has purulent drainage from an old IV site, with either no or a negative blood specimen, how is this reported to NHSN?

Consult the criteria for VASC-Arterial or Venous Infection available in Chapter 17 pdf icon[PDF – 1 MB], available on page 17-15.  Such a patient would meet criterion 4.  If your facility is monitoring for these types of infection, enter this into NHSN as a CVS-VASC event.

Pus at the vascular access site

Q21. How do I report an event into NHSN when a patient has the following scenario during the BSI infection window period?

  • Both a central line and another vascular access device in place
  • Pus at the other vascular access device site
  • Matching organisms from the vascular access site and blood specimen

Please see Note: #d, under the Comments and Reporting Instructions found in Chapter 4 BSI pdf icon[PDF – 2 MB] protocol for guidance. This guidance states:

Occasionally, a patient with both a central line and another vascular access device will have pus at the other access site. If there is pus at the site of one of the following vascular access devices and a specimen collected from that site has at least one matching organism to an organism identified in blood report such events, marking the “pus at the vascular access site” field as “Yes.” In this situation, enter “Yes” on the event form in the NHSN application for the field “Central Line?” However, you should include the patient’s central line days in the summary denominator count. Vascular access devices included in this exception are limited to:

  • Arterial catheters
  • Arteriovenous fistulae
  • Arteriovenous graft
  • Atrial catheters (also known as transthoracic intra-cardiac catheters, those catheters inserted directly into the right or left atrium via the heart wall)
  • Hemodialysis reliable outflow (HERO) dialysis catheters
  • Intra-aortic balloon pump (IABP) devices
  • Non-accessed central line (not accessed nor inserted during the hospitalization)
  • Peripheral IV or Midlines

Intra-aortic balloon pumps (IABP)

Q22: Are intra-aortic balloon pumps (IABP) considered central lines?

Because IABPs are not considered central lines because they are generally not used for infusion, blood withdrawal, or hemodynamic monitoring. Do not include IABP device days in the central line day count.


Q23: Does NHSN consider IABP the same as a ventricular assist device (VAD)?

IABPs are not considered ventricular assist devices.  The bloodstream infection risks associated with IABP devices is different from an NHSN surveillance perspective.

Femoral arterial lines

Q24: Are femoral arterial lines considered central lines in NHSN?

Because the femoral artery is not among the list of great vessels defined for CLABSI surveillance in NHSN, a catheter in this vessel is not considered a central line. Do not include femoral artery catheter days in the central line day count.

Dialysis patients

Q25.  If an in-patient who is provided dialysis by dialysis staff, either in the patient’s room or in the dialysis unit, develops a CLABSI, to which location is the CLABSI attributed?  Our unit nursing staff does not access the dialysis catheter and it is the patient’s only central line.

In both situations, the CLABSI must be attributed to the inpatient location where the patient is housed overnight. The dialysis unit is defined as an inpatient unit that provides services to inpatients. It is also a non-bedded location that does not keep patients overnight; therefore, CLABSI surveillance for NHSN reporting purposes cannot be performed in this location because there can be no patient or central line day counts. Likewise, dialysis performed in the patient’s room by dialysis staff cannot be attributed to the dialysis unit. The BSI event form in the NHSN application contains the following required field “Any hemodialysis catheter present?” The data in this field can be analyzed using NHSN output options which can be used internally by facilities to identify and track issues believed to be related to dialysis care.

Chronic dialysis patients

Q26: When performing central line-associated bloodstream infection (CLABSI) surveillance in an inpatient dialysis location, should chronic dialysis inpatients be included?

Yes. If CLABSI surveillance in an inpatient dialysis location is part of your monthly reporting plan, all patients in that location must be included in CLABSI surveillance. (NOTE: inpatient dialysis locations that are non- bedded locations, in other words, patients do not spend the night in these locations, but instead are transported there for dialysis and then return to a bedded location for the remainder of their care, cannot participate in the NHSN CLABSI protocol at this time). See question and answer directly above.

Contracted staff

Q27: How should a CLABSI be reported when the central line is only accessed by contracted dialysis staff?

Facilities are responsible for all patient care provided in the facility by employed and contracted staff alike. Therefore, all CLABSIs identified in these patients are attributed to the in-patient unit where the patient is physically located.

Patient reported fever

Q28: Can I use patient reported fever to meet CDC/NHSN LCBI criterion 2 or 3 for present on admission (POA)?

Patient reported signs and symptoms can be used as an element to meet CDC/NHSN site-specific criteria provided it occurs during the IWP. When fever is the symptom, the patient must report an objective finding (specifically, temperature of >100.4 F).  Subjective statements (such as, “I felt feverish”) are not acceptable and are excluded. Documentation of signs/symptoms from a transferring facility are also acceptable provided they occur during the POA timeframe (2 days prior to admission, the day of and the day after admission) and are documented in the current medical record. For example, a patient is transferred from a nursing home is afebrile upon admission to the hospital, but nursing home documentation indicates the patient had a fever the morning of transfer. If the nursing home documentation and/or report of the fever is included as part of the patient’s current admission, then it can be used as an element to meet CDC/NHSN LCBI criteria 2 or 3.

Patient suspected of injecting into vascular catheter

Q29: If an inpatient is suspected of accessing their own vascular catheter, specifically, injecting illicit drugs, and a BSI develops, is the BSI attributed to the facility?

A positive blood specimen meeting an LCBI criteria, that is accompanied by documentation, during the infection window period (IWP), of observed or suspected patient injection into vascular access lines, will be excluded from CLABSI surveillance. This exclusion is very specific to INJECTION into the line (tampering with, manipulating, etc. do not meet the intent of the exclusion). For example, “pulling on the line, picking at the dressing, removing the caps, and biting” are just a few examples of line manipulation that do not meet the requirements of this exception. These actions are different from the purposeful injection into a vascular line that is common among IVDA’s. IVDA’s, may inject their own line without regard for proper line use and/or management, putting their health and safety at risk.

Injection, in this exclusion, is limited to patient injections only and does not include injections performed by other healthcare providers whether employed, contracted, family members, or visitors.  These events are still considered LCBIs but are not associated with the central line and therefore, are not CLABSIs for NHSN reporting purposes. A BSI repeat infection timeframe (RIT) is created during which no new BSI events will be reported but any additional organisms identified are added to the initial event. Positive blood specimens collected outside of the BSI RIT must be investigated and must meet the documentation requirements again within the IWP. If addendums to the patient medical record are made regarding observed or suspected patient injection during the BSI IWP, the addendum must be documented within 30 days of discharge to be eligible for the exclusion.  If reporting the BSI to NHSN, answer “Yes” to the risk factor field “Central line”.

Vital Signs (hypotension, apnea, bradycardia)

Q30: What is the definition of these vital signs when evaluating common commensals for meeting LCBI 2 or 3 criteria (CLABSI)?

NHSN does not define a specific value for these vital signs. Instead, each facility should use the vital sign parameters as stated in their policies and procedures for clinical documentation. The presence of any of these vital signs before the IWP does not exclude the event from meeting LCBI 2 or 3 criteria.  An LCBI 2 or 3 criteria can be cited if an eligible vital sign occurs during the BSI IWP.

Reporting Locations

Q31: In addition to ongoing ICU surveillance, what locations are now required to be included in reporting CLABSI for participation in CMS quality reporting programs?

Information on locations that are included in reporting can be found in the Operational Guidance for Acute Care Hospitals to Report Central Line-Associated Bloodstream Infection (CLABSI) pdf icon[PDF – 200 KB] . The Centers for Medicare and Medicaid Services are the ultimate source for identifying reporting required as part of their programs.

Submitting a BSI case review to NHSN

 Q32: What information is needed to assist with a primary BSI or secondary BSI determination?

For NHSN to assist with a primary or secondary BSI case determination please send the following information to nhsn@cdc.gov:

If investigating a positive blood culture:

  • Admission date
  • Central line insertion date
  • Central line discontinuation date if applicable
  • Date(s) and results of any positive blood cultures
  • All organisms identified in the blood culture(s)
  • Signs/symptoms and associated dates if evaluating LCBI-2/3 criteria
  • Date of first access in an inpatient location (if patient is admitted with a central line in place)
  • MBI LCBI risk factors (if evaluating MBI LCBI criteria)

If evaluating for a secondary BSI:

  • Site specific infection under consideration (for example Chapter 17 infections, SSI, UTI, PNEU)
  • Supporting documentation (for example any positive blood cultures, imaging results, or sign/symptoms and associated dates if applicable)
  • Date(s) and results of any positive blood cultures
  • All organisms identified in the blood culture(s) (include information on whether the organisms are in the same blood culture or two separate blood cultures)
  • Any information on recent NHSN surgical procedures (including the operative report and any imaging performed)


Q33. Does my facility need to report the CLABSI exclusions to NHSN?

Yes, these events should be reported to NHSN.  Although these events are reported they are NOT considered central line associated and they DO NOT contribute to the CLABSI SIR measure.  Exclusions include:

  • Extracorporeal life support (ECLS [for example ECMO])
  • Ventricular assist device (VAD)
  • Patient self- injection
  • Epidermolysis bullosa (EB)
  • Munchausen syndrome by proxy (MSBP)
  • Pus at the vascular access site

Gross Anatomical Exam

Q34. What is acceptable evidence of infection found on gross anatomic exam?

Evidence of infection elicited or visualized on physical examination or observed during an invasive procedure.  This includes findings elicited on physical examination of a patient during admission or subsequent assessments of the patient and may include findings noted during a medical/invasive procedure, dependent upon the location of the infection as well as the NHSN infection criterion.


  • An intraabdominal abscess will require an invasive procedure to visualize the abscess.
  • Visualization of pus or purulent drainage (includes from a drain).
  • SSI only: Abdominal pain or tenderness post Cesarean section (CSEC) or hysterectomy (HYST or VHYS) is sufficient evidence of infection detected without an invasive procedure to meet general Organ/Space SSI criterion “c”.  Allowing the documentation of abdominal pain or tenderness as gross anatomic evidence of infection to meet general Organ/Space SSI criterion “c” allows the SSI determination to move on to meet a site-specific organ/space infection criterion.

NOTE: Imaging test evidence of infection cannot be applied to meet gross anatomic evidence of infection.  Imaging test evidence has distinct findings in the HAI definitions (for example, IAB 3b).

MBI RIT Exception

Q34. What is the MBI RIT Exception?

An MBI-LCBI designation will not change to an LCBI event if the two criteria below are met:

  1. The positive non-MBI blood culture is collected during an MBI-LCBI BSI RIT
  2. The positive non-MBI blood culture can be deemed secondary to an NHSN site-specific infection

Please see Example 2b in Chapter 2 pdf icon[PDF – 1 MB], page 2-20.

Non-culture Based Testing Method (NCT)

Q36: Are non-culture-based testing (NCT) methods eligible for use to meet LCBI-1 criterion?

Yes, NCT methods are eligible for use to meet LCBI-1 criterion. If an organism is identified to the genus or species level by non-culture based microbiologic testing methods.

Note: If blood is collected for culture within 2 days before, or 1 day after the NCT, disregard the result of the NCT and use only the result of the CULTURE to make an LCBI surveillance determination. If no blood is collected for culture within this time period, use the result of the NCT for LCBI surveillance determination


Organism(s) identified in blood is not related to an infection at another site (See LCBI-1 Criterion in the BSI Chapter pdf icon[PDF – 1 MB]).


Are non-culture-based testing (NCT) methods eligible for use to meet LCBI-2 or LCBI-3 criteria?

No, LCBI-2 and LCBI-3 criteria are only met using matching organisms identified by a blood culture plus signs and symptoms. (See LCBI-2 and LCBI-3 criteria in the BSI Chapter pdf icon[PDF – 1 MB]).