Blood culture

What is a Blood Culture? (Blood C&S)

Protocol

For the purpose of the ICU lab count collection we are counting the number of sites and not sets. Our guidelines for counting blood cultures have nothing to do with any other guidelines or criteria. For example: Blood drawn from one site inoculated into any number of bottles=1 Blood drawn from two sites inoculated into any number of bottles=2

This was discussed and decided by Dr Garland at the task meeting on August 21,2014

Tina will move this discussion below.

A blood culture is a microbiological "procedure" that is ordered as a set.

One set consists of 2 to 3 bottles of blood from two different sites within a very short time of each other. (1 or 2 aerobic bottle & 1 anaerobic bottle)

The set is counted as ONE blood culture for Labs collected list.

Hospital all have a nursing procedure protocol.

samples not taken to protocol

Even if samples are not taken to protocol, count it as a blood culture. Example:

• 2 bottles from 1 venipuncture site, this is not a complete blood culture and the question is "why would a unit not be following a protocol"?
  • This should only be counted as ONE SET of blood cultures.
    • 1 aerobic and 1 anaerobic bottle from 1 site = 1 count//// 2aerobic and 2 anaerobic bottles =4 bottles from 2 different site = 2 count Is this not correct? We spoke with micro here at the Vic when getting blood cultures from a peripheral poke you draw one aerobic and one anaerobic bottle and because it is peripheral ,the lab wants a control sample( to rule out if it is a contaminent) from a second peripheral site doesnt need to be a new poke can be from old lok.>24 hours) which = 1 count

article related to

• Central Line Related Blood stream Infection (CLR-BSI)
• Septic Shock
• QA Septic Shock
• Septicemia/Bacteremia/Fungemia,
• Urosepsis

Discussion

• CULTURE and the CENTRAL LINE RELATED INFECTION categories seem to contradict each other on the wiki in terms of what ONE SET of blood cultures are.

• Under the category BLOOD CULTURE it reads (in part):

• A blood culture is a microbiological "procedure" that is ordered as a set. One set consists of 2 to 3 bottles of blood from two different sites within a short time of each other. (1 aerobic bottle & 1 or 2 anaerobic bottle) . The set is counted as ONE blood culture for Labs collected list.

• On the wiki under CENTRAL LINE RELATED INFECTION the ‘definition’ of blood cultures reads (in part)

• One blood culture is defined as one site (at least one of two bottles from a Blood culture set is reported as having grown at least one organism).
  • Hi, I was looking at this one and the above has to do with one of two bottle, one of which has an organism. Good catch, will have to look at this one. A blood culture is two or more bottles from two site.

• On the wiki under central line related infection it also states:

• Separate occasions for the Blood cultures can range from 15 minutes apart to within 48 hours of each culture.
  • yes that is correct, the 5 mins apart has been removed, it was a minimal guideline. When drawing a blood culture SET, obviously a nurse can't draw from two different sites at the same time........but if drawing 15 mins apart or more this is considered to be a separate blood culture SET.

• Different ports of the same line is considered 2 sites.

• Here are my thoughts to make it consistent. As nurses should know that:

• • When blood cultures are ordered, it means that blood is to be drawn from 2 different sites to make a complete blood culture set.

• • The order is often written as “Blood cultures X 2” indicating that we are to collect blood from 2 sites (common knowledge)

• • Sometimes patients have very difficult peripheral venous access and it is impossible to get a complete set of cultures, so sometimes only one or two bottles are sent instead of the full set, and only from one site

• • Sometimes after getting only one or two bottles of a blood culture set peripherally from one site the pt may then have an arterial line and/or a central line inserted and then the nurse sends blood culture bottles from the arterial and central lines– usually a complete set of bottles, which exceeds the required number of bottles sent for an actual blood culture set ( if you count the peripheral set sent earlier). (The extra bottles are sent because those lines are put in under a sterile procedure and are less likely to have a microorganism that is a contaminant).

• • Sometimes the delay between sending the initial peripheral blood culture bottles and the blood culture bottles from the arterial and/or central line can be a few hours and certainly exceeds 5 minutes or so (as outlined on the wiki definition of blood culture)

• • Given these points that I have raised, I would find it LEAST confusing from a data collector’s point of view to actually count the number of SITES from which blood is taken instead of counting the number of blood cultures, because in the clinical setting there is often a discrepancy between

• • the number of bottles actually sent for a blood culture set, and

• • the time lapse between the bottles that are sent (it can exceed the 5 minutes that the blood culture definition on wiki uses)

• By counting each SITE as a blood culture, there is a concrete number that is not subject to interpretation of a ‘set’ and the data collected will be more consistent. I realize that the true definition of blood cultures varies from this. However, blood culture orders are often written as “blood cultures X 2” so when the situation is ideal and cultures are collected in a routine fashion without delay, the number '2' in the labs section of our data would be recognized/interpreted as one blood culture set. However, because of the less than ideal clinical situations that occasionally make it difficult to send a true set of blood cultures, each data collector ends up using their own interpretation of what constitutes a blood culture when there were ‘incomplete’ blood culture sets or blood sent from more than 2 sites with (or without) a time delay--Jthiessen 15:17, 2014 August 7 (CDT)