Urine Culture and Sensitivity Lab Values

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Outline

Objectives:

Determine the significance and clinical use of evaluating Urine Culture and Sensitivity in clinical practice

 

Lab Test Name:

Urine Culture and Sensitivity

 

Description:

Urine culture and sensitivity is a lab test performed on urine in a patient with S/S of a urinary tract infection or symptoms of bladder irritation. 

The culture evaluates if any bacteria grows in the sample. The sensitivity is valuable in selecting the correct antibiotic that will kill the bacteria that grew out in the culture. 

Urine culture 

  • Evaluates for bacterial growth

Sensitivity

  • Tests antibiotic sensitivity on the cultured sample
  • Identifies the offending bacteria
  • Identifies antibiotic that will kill said bacteria
  • Antibiotic selection

 

Indications:

Indicated:

  • S/S Urinary tract infection
  • S/S Bladder irritation

Test Results and Collection Process:

Normal –  

  • No growth – absence of bacteria in the urine

Abnormal –

  • Culture positive for bacterial growth

Sensitivity – 

  • Determines bacterial survivability when exposed to various antibiotics
  • Aids antibiotic selection

Collection:

  • Clean catch – clean catch is performed by the patient. They are instructed to thoroughly clean the exterior of their genitals with a provided solution or packaged cloths. With a cleansed exterior, the culture will be more accurate in only growing microbes in the urine rather than growing bacteria that could be present via cross-contamination from the skin
  • Specimen collection via catheter
    • Indwelling
    • Intermittent catheterization for sample collection

 

What would cause increased levels?

N/A for this lesson. See other parts of outline for explanation of test results

 

What would cause decreased levels?

N/A for this lesson. See other parts of outline for explanation of test results

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Transcript

Hey everyone, Abby here with nursing.com. In this lesson, we’ll discuss urine culture and sensitivity. We’ll talk about normal results versus abnormal results, and what sensitivity means. Let’s get started. 

 

Urine culture and sensitivity is a two-part testing system to identify if there is bacterial growth and which antibiotic will actually kill the bacteria that’s in the urine. So, the culture itself is when the urine is taken and applied to a Petri dish to see what grows. Now, the sensitivity part comes in when they test the antibiotic on the cultured sample. What it does is, it identifies the offending bacteria. Once it’s identified that that antibiotic will kill the bacteria, we can use that as our selection in treating the patient. 

 

Some clinical indications for why this would be done are for signs and symptoms of urinary tract infection, or bladder irritation, and this is that Petri dish I was talking about. There’s usually some sort of nutrient base like agar or, um, some type of jelly that the bacteria grows really well on, and you can see here, that the bacteria has actually been applied to the sample and it’s growing. The sensitivity phase is when antibiotics are actually applied to this sample to see if bacterial growth is inhibited. 

 

So, a normal sample, or what we would want to see is the absence of bacteria in the urine, or no growth on our sample. It would be abnormal if the culture was positive for bacterial growth, and then it would go into sensitivity testing, and then sensitivity determines the bacterial survivability upon exposure to those antibiotics. This is going to help us decide that we’ve got the right drug for the right bug. Okay. Now, the way that we collect this specimen is it can either be done by the patient themselves, or by the RN, or support staff. The clean catch method, the patient does it themselves. They’re given these little cloths, they usually have alcohol or some type of solution on them, or castile soap or something, and they use that to clean their external genitalia, to avoid cross contamination of their skin getting into the sample. 

 

We want just what the urine is going to grow, not what is on the skin, and so we also want to make sure that we encourage them to not touch the inside of the lid or the inside of the cup when we give them that specimen collector. Now, it can also be done via catheter. If it’s done via an indwelling catheter, we do not want to measure it from the bag, we want to get it from the tubing and do it in as sterile of a manner as possible. It can also be collected via intermittent catheterization, which is when a catheter is inserted, the sample is obtained, and then the catheter is taken out, unlike indwelling, when it stays in. 

 

The linchpins for this lesson are that urine culture and sensitivity are evaluated when a patient, uh, presents with signs and symptoms of a urinary tract infection or bladder irritation. What it does is, determines if there is infection and identifies the bacteria, so that we definitely are having the right drug for the right bug, it’s sensitive to that antibiotic. A normal, uh, result would be to have no growth on our agar, whereas if it’s abnormal, there will be growth on the culture medium like we saw on that one slide. Sensitivity, just to roll over that again, is the actual testing phase to see which antibiotic is actually specific to killing that bug. We don’t want to overuse antibiotics. 

 

Now you’ve all done great on this lesson. This wraps it up. We love you guys. Now go out, be your best self today and as always, happy nursing.

References:

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