blood cultures after antibiotics

2shihtzus · Oct 3, 2010

They "should" be taken before abx are given. However, there is always a chance that the culture may grow something that is resistant to the abx that the pt is currently on. Also, it takes a while before the abx get rid of the current infection.

GM2RN · Oct 3, 2010

It's entirely probable that the first set of cultures was already done in the ED. And the previous post is correct. The pt could be infected with something resistant to the current antibiotic, which may be why he/she spiked a temp, so getting another set of cultures is indicated.

canesdukegirl, BSN, RN · Oct 3, 2010

In the perfect world yes, BC should be done prior to administering ABX. However, if abx are given, note the abx and time given on the label of the BC tube so that the lab has that info.

BittyBabyGrower, MSN, RN · Oct 3, 2010

Yes, you can repeat blood cultures if the patient is on antibiotics...we routinely repeat ours for certain infections such as yeast. Sometimes you have a resistant bug or one that is slow to clear.

RNBSNxo · Oct 3, 2010

you do blood cultures at first spike and then start antibiotics but you dont stop there. here, every 24hrs a culture is redrawn when a patient spikes IF they have a central line. maybe the current antibiotic they are on doesnt cover the infection they have. another antibiotic may be needed. there can still be an infection in the line or bloodstream.

rn4ever? · Oct 4, 2010

Well, let's say the pt has UTI and is on antibiotic A. Then a new wound of pt gets cultured and tests + for MRSA. So now the pt may need another antibiotic because antibiotic A will not address the new issue. So it's possible to culture a pt who is already on antibiotic treatment. But in our place of work, there is a space in the form that gets sent down to the lab (with the specimen) to indicate if the pt is already on an antibiotic treatment (and you should indicate too what type it is).

highlandlass1592, BSN, RN · Oct 4, 2010

You will culture a patient before they go on antibiotic therapy if possible. Some patients develop s/s infection while already on antibiotics (say routine post-ops who are finishing a course). So you re-culture (in this instance) to see if an infection has developed. And while on antibiotics, they may do daily blood cultures to make sure the anti-biotics are "clearing" the infection. As someone else pointed out, it takes 3 to sometimes 4 days to get a final culture report back and if positive to get it speciated. You may find you are using the incorrect therapy and need to change the antibiotics being administered.

And let's say this patient is going to need to go home on IV antibiotic therapy. In our facility, these patients will need to go home with a PICC line. They can't get a PICC till the cultures clear (which means the antibiotics are working) because of the greater risk of infecting the line and causing a super infection. There is actually a lot going into figuring out antibiotic therapy...pretty interesting I think.

**canoehead, BSN, RN** · Oct 5, 2010

The lab can also use a different tube to draw when a patient is already on antibiotics. It has a substance that binds with the antbiotic that is left in the blood so whatever bugs are there are free to grow in culture. I'm sure it's not foolproof, but it's better than not getting cultures done at all.

BluegrassRN · Oct 5, 2010

On most of our pts with a dx of sepsis or pneumonia, even though blood cultures are routinely drawn in ED prior to administration of initial dose of medication, if the pt spikes a temp > 38.5 or if the temp drops below 36, or if they develop rigors, we typically draw blood cultures again.

It's what our hospitalists like to do, so if there isn't an order, I will usually call and ask anyway. Better safe than sorry, don't want to miss the opportunity to identify an organism just because a green ED doc forgot to order a prn blood culture.