This test requires a urine sample. The sample is taken by placing a thin rubber tube (called a catheter) through the urethra into the bladder. A nurse or a trained technician may do this.
First, the area around the opening of the urethra is thoroughly washed with a germ-killing (antiseptic) solution. The tube is inserted into the urethra. The urine drains into a sterile container, and the catheter is removed.
Rarely, the health care provider may choose to collect a urine sample by inserting a needle directly into the bladder and draining the urine. However, this is usually only done in infants or to immediately screen for bacterial infection.
The urine is sent to a laboratory. Tests are done to determine if there are germs in the urine sample. Other tests may be done to determine the best medicine to fight the germs.
How to prepare for the test
Do not urinate for at least 1 hour before the test. If you don't have the urge to urinate, you may be instructed to drink a glass of water 15-20 minutes before the test. Otherwise, there is no preparation for the test.
How the test will feel
There is some discomfort. As the catheter is inserted, you may feel pressure. If you have a urinary tract infection, you may have some pain when the catheter is inserted.
Why the test is performed
The test is done:
To get a sterile urine sample in a person who cannot urinate on their own
If you might have a urinary tract infection
If you cannot empty your bladder (urinary retention)
Normal values depend on the test being performed. Normal results are reported as "no growth" and are a sign that there is no infection.
What abnormal results mean
A "positive" or abnormal test means germs, such as bacteria or yeast, are found in the urine sample. This likely means that you have a urinary tract infection or a bladder infection. If there is only a small amount of germs, your health care provider may not recommend treatment.
Sometimes, bacteria that do not cause urinary tract infections may be found in the culture. This is called a contaminant. You may not need to be treated.
Perforation (hole) in the urethra or bladder from the catheter
Hooton TM, Bradley SF, Cardenas DD, et al. Diagnosis, prevention, and treatment of catheter-associated urinary tract infection in adults: 2009 International Clinical Practice Guidelines from the Infectious Diseases Society of America. Clin Infect Dis. 2010;50(5):625-663.
Ban KM, Easter JS. Selected urologic problems. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, Pa: Mosby Elsevier; 2009: chap 97.
Dean AJ, Lee DC. Bedside laboratory and microbiologic procedures. In: Roberts JR, Hedges JR, eds. Clinical Procedures in Emergency Medicine. 5th ed. Philadelphia, Pa: Saunders Elsevier; 2009:chap 68.
David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc; Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Bellevue, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine.