mjbapana
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Can anyone tell me in Infective endocarditis why do u have to take 3 blood cultures from 3 different sites at 1 hr intervals.thanx.
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Philippians, chapter 4verse 13 : "I can do all things through Him who strengthens me."
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| SILVER
DoWhatYouGotToDo!
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Never draw only one set of blood cultures; one is worse than none. For diagnosing subacute IE, draw 3-5 sets of blood cultures over 24 hours. This helps detect 92-98% of cases in patients who have not recently received antibiotics. In the case of acute IE, 3 sets may be drawn over 30 minutes (with separate venipunctures) to help document a continuous bacteremia.
Reference: http://www.emedicine.com/med/topic671.htm
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| bactitech
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Standard BC draw is now 2-3 sets/24 hour period with, ideally, 5-10 ml blood per BOTTLE. We NEVER see five sets on one patient in a 24 hour period unless there is a duplicate order or a screw-up of orders [sorry]. That being said, it is highly important that each set be drawn via a separate stick. This is because there is no way of determining whether skin contamination has occurred if only one set turns positive for something like coagulase negative Staph or even a Streptococcus viridans (which CAN be implicated in endocarditis).
Yes, just drawing one BC is pretty dumb, because if your only set turns positive with CNS you have nothing to compare it to and are obligated to treat. We see this ALL the time, unfortunately. For the record, our lab sees 81,000 bottles (not sets) in a year. That figure was from a few years back - it's probably more now. We are loading blood culture bottles onto our VersaTrek constantly.
Still, standard ER procedure in many hospitals seems to be to get one set during the poke to start an IV - or even two sets at this time. Then all four bottles become positive for CNS and the patient is forced to endure antibiotics that probably were not necessary and stay longer in the hospital, driving up health care costs. This is a battle we are trying to wage with ER now, and many micro labs wage with ER on a daily basis. It is like pulling teeth to get them to stop this practice. By saving the patient a stick you cost them thousands of dollars in extra costs (or the hospital, depending who is paying) if a set turns out to harbor a possible skin contaminant.
For the record - blood cultures should [ideally] NOT be drawn off of indwelling lines or at IV start because of this. The skin should be prepped properly with the provided skin scrub. THIS IS VERY IMPORTANT. If one is drawn from a line, another should be drawn from a venipuncture to compare results. Many times lines are colonized and the infection "goes away" when the line is changed or removed.
Our lab performs micro work (including blood cultures) for four hospitals. Our machines were FULL this weekend with the influx of fever-related BC draws typical of this time of year.
Not to chide you guys, but must one really draw blood cultures on EVERY patient with a temperature increase? This happens every winter and I find it hard to believe that these are not CYA blood cultures as opposed to ones necessary due to medical history (just crabbing - we had a horribly busy New Year's Day on the evening shift and last weekend was nasty also). I really do think the "standard" order is CBC, lytes, and BC X 2 on anyone with a temp above 99 degrees.
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Clinical Microbiology since 1974
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| mjbapana
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thanx silver and bactitech for u r replies.
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Philippians, chapter 4verse 13 : "I can do all things through Him who strengthens me."
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| mjbapana
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Topics: 32
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thanx silver and bactitech for u r replies.
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Philippians, chapter 4verse 13 : "I can do all things through Him who strengthens me."
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