Urine Culture

How does a urine culture work?

You can provide a urine sample by peeing into a cup, following your provider’s instructions. Or, if you or your child aren’t able to give a sample this way, your provider can use another method (like catheterization or a urine bag). Your provider will send the pee to a lab.

A lab technician will dip a stick with a small loop at the end into the sample. They’ll spread it onto a plate with nutrients that encourage any microorganisms to grow. If you have a UTI, many patches (colonies) of bacteria or yeast will grow on the plate within a day or two. The lab technician will examine and count the colonies to provide your results.

If bacteria or fungi grow in your sample, the lab will test the culture for antibiotic sensitivity (or antifungal sensitivity). An antibiotic sensitivity (or susceptibility) test identifies which antibiotics kill them or stop their growth. This information helps your healthcare provider select an antibiotic medicine.

How do I prepare for a urine culture?

Your healthcare provider will let you know if you need to take any special steps before providing a urine sample. They may ask you to:

• Not pee for at least an hour before giving a urine sample.
• Drink at least 8 ounces of water 20 minutes before the sample collection to ensure there’s enough pee to test.
• Collect your pee first thing in the morning.

Let your provider know if you have trouble peeing away from home, or shy bladder syndrome. They can give you ways to provide a sample that’s comfortable for you.

What happens during a urine culture?

A urine culture requires a clean catch urine sample. This means your sample is as free of outside contaminants as possible, such as normal bacteria that live on your skin. You might provide this sample at your healthcare provider’s office or a lab testing facility. In certain situations, you might collect it at home.

To collect a clean catch urine sample:

1. Wash your hands with soap and warm water.
2. Use an antiseptic wipe to thoroughly clean your vulva and vaginal area or the head of your penis. If your penis is uncircumcised, first pull back your foreskin to ensure a thorough cleaning.
3. Let out a small amount of pee into the toilet and stop midstream.
4. Place a sterile cup under your vulva or penis before you start peeing again. Don’t let the cup touch your skin.
5. Fill the cup about halfway or to the amount your provider recommends. It’s OK if you can’t fill it quite halfway.
6. If you need to pee more, stop midstream (if you can), hold the cup out of the way and finish peeing in the toilet.
7. If your provider gave you a lid, place it on the cup. Your provider should tell you where to leave the cup when you’re done. Don’t forget to wash your hands again.

What are other ways to collect a urine sample?

For anyone who isn’t able to collect a sample themselves (like a young child or someone who’s ill), a healthcare provider may use one of these methods:

• Catheterization: A provider inserts a catheter (thin, flexible tube) through your urethra into your bladder. Pee flows from the catheter into a sterile collection bag.
• Urine bag (U bag): For infants and young children, your provider might have you attach a urine collection bag with sticky adhesive directly to their penis or over their vulva. After your child pees, empty their pee into the container provided. If you’re collecting at home, keep the container refrigerated until you drop it off at a lab or your healthcare provider’s office.
• Aspiration: A provider inserts a thin needle through numbed abdominal skin and into your bladder. They draw pee from your bladder into a collection bag.

What are the risks of a urine culture?

It’s very safe to provide a urine sample through the clean catch or U bag method. There’s a slight risk of infection with the catheter or needle method. The biggest risk is that the sample is contaminated with bacteria or yeast from your skin. This could make your results inaccurate (false positive).

How long does a urine culture take?

Cultures need 24 to 48 hours to grow. It might take up to three days for the lab to complete the test and send back the results. Your provider will contact you with the results or they’ll show up in your electronic health records.

What does a positive urine culture test result mean?

If your urine culture is positive and you have symptoms of an infection, it means you have a UTI. If they haven’t already, your provider will start you on medication to treat the infection.

You can also have bacteria in your pee without any symptoms (asymptomatic bacteriuria). You usually don’t need treatment if you don’t have symptoms.

If the lab ran an antibiotic or antifungal sensitivity test, you may see the following results:

• Susceptible. This means the medicine worked to stop the growth or kill the specific bacteria or fungus grown in your culture. It should be the first choice to treat the infection.
• Intermediate. This means the medicine had some effect on stopping the bacteria or fungus. At higher doses, it might be effective for treating the infection.
• Resistant. This means the medicine didn’t work to stop or kill the bacteria or fungus. It shouldn’t be used to treat the infection.

What does a negative urine culture test result mean?

A negative, or normal, urine culture test result means the urine sample showed no signs of bacteria or yeast. You don’t have a UTI. The range for normal test results can vary depending on the lab doing the test.

There can be other causes of UTI-like symptoms, such as menopause-related changes, kidney stones or bladder masses. If you continue to have pain when you pee, an urgent or frequent need to pee, or blood in your pee (hematuria), you should have more testing to find the cause. Your healthcare provider may recommend imaging scans, additional testing and/or referral to a urologist.

When should I call my doctor?

Talk to your healthcare provider if your symptoms aren’t improving after treatment or if you have questions about the results of the test.