Culture and sensitivity - urine
A urine culture is a lab test to check for bacteria or other germs in a urine sample.
How the Test is Performed
Most of the time, the sample will be collected as a clean catch urine sample in your health care provider's office or your home. You will use a special kit to collect the urine.
A urine sample can also be taken by inserting a thin rubber tube (catheter) through the urethra into the bladder. This is done by someone in your provider's office or at the hospital. The urine drains into a sterile container, and the catheter is removed.
Rarely, your provider may collect a urine sample by inserting a needle through the skin of your lower abdomen into your bladder.
The urine is taken to a lab to determine which, if any, bacteria or yeast are present in the urine. This takes 24 to 48 hours.
How to Prepare for the Test
If possible, collect the sample when urine has been in your bladder for 2 to 3 hours.
How the Test will Feel
When the catheter is inserted, you may feel pressure. A special gel is used to numb the urethra.
Why the Test is Performed
Your provider may order this test if you have symptoms of a urinary tract infection or bladder infection, such as pain or burning when urinating.
You also may have a urine culture after you have been treated for an infection. This is to make sure that all of the bacteria are gone.
Using the bathroom is usually a no-brainer. You go, you flush, you wash. But sometimes, you can have a condition that makes it painful or difficult to go. If you're feeling pain or burning when you urinate, or you feel like you need to go all the time, the problem could be a urinary tract infection. Most often, you get a urinary tract infections when bacteria make their way into your bladder, kidneys, ureters, those tubes that carry urine from the kidneys to the bladder, or the urethra, the tube that carries urine to the outside of your body. Unfortunately for women, they're more likely to get a urinary tract infection than men because they have a much shorter urethra. Bacteria can more easily slip into a woman's body after they have sex or use the bathroom. Certain conditions can also increase your risk of a urinary tract infection, including diabetes, pregnancy, kidney stones, an enlarged prostate in men, as well as urinary tract surgery. You can often tell you may have a urinary tract infection by the pain and burning whenever you urinate, and the constant urge to go. Your urine may look cloudy or bloody, and it might give off a bad smell. Your doctor can diagnose an infection by taking a urine sample and checking for bacteria. Occasionally different scans, including a CT and kidney scan, may be done to rule out other urinary problems. If you do have a urinary tract infection, you'll probably be prescribed antibiotics, drugs that kill bacteria. Also drink a lot of water and other fluids to help flush out the bacteria. Usually, antibiotics can knock out a urinary tract infection in a day or two. But like the unwelcome visitors they are, sometimes these infections keep coming back. You may need to keep taking antibiotics for a longer period of time. There are ways to help prevent getting urinary tract infections, like drinking a lot of fluids, perhaps including cranberry juice. Probiotics, beneficial bacteria may also help prevent urinary tract infections. Women should be careful about their hygiene. Always wipe from front to back after using the bathroom, urinate before and after sexual activity, and keep your genital area clean. If you use a diaphragm with spermicide, consider changing contraceptives. For post menopausal women, topical estrogen greatly reduces urinary tract infections. Recurrent, uncomplicated urinary tract infections are very common in non pregnant, healthy young women. Thankfully, they are easy to treat and are unlikely to lead to other health problems.
"Normal growth" is a normal result. This means that there is no infection.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
What Abnormal Results Mean
A "positive" or abnormal test is when bacteria or yeast are found in the culture. This likely means that you have a urinary tract infection or bladder infection.
Other tests may help your provider know which bacteria or yeast are causing the infection and which antibiotics will best treat it.
Sometimes more than one type of bacteria, or only a small amount, may be found in the culture.
There is a very rare risk of a hole (perforation) in the urethra or bladder if your provider uses a catheter.
You may have a false-negative urine culture if you have been taking antibiotics.
Dean AJ, Lee DC. Bedside laboratory and microbiologic procedures. In: Roberts JR, Custalow CB, Thomsen TW, eds. Roberts and Hedges' Clinical Procedures in Emergency Medicine and Acute Care. 7th ed. Philadelphia, PA: Elsevier; 2019:chap 67.
Germann CA, Holmes JA. Selected urologic disorders. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 89.
Schaeffer AJ, Matulewicz RS, Klumpp DJ. Infections of the urinary tract. In: Wein AJ, Kavoussi LR, Partin AW, Peters CA, eds. Campbell-Walsh Urology. 11th ed. Philadelphia, PA: Elsevier; 2016:chap 12.
Last reviewed on: 10/8/2018
Reviewed by: Linda J. Vorvick, MD, Clinical Associate Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.