Urine culture - clean catch; Clean catch urine specimen
A clean catch is a method of obtaining a urine sample to be sent for various tests, including urinalysis and urine culture.
How the test is performed
Collect a “clean-catch” (midstream) urine sample. To obtain a clean-catch sample, men or boys should wipe clean the head of the penis. Women or girls need to wash the area between the lips of the vagina with soapy water and rinse well. As you start to urinate, allow a small amount to fall into the toilet bowl (this clears the urethra of contaminants). Then, in a clean container, catch about 1 to 2 ounces of urine and remove the container from the urine stream. Give the container to the health care provider or assistant.
For an infant:
Thoroughly wash the area around the urethra. Open a Urine collection bag (a plastic bag with an adhesive paper on one end), and place it on your infant. For males, the entire penis can be placed in the bag and the adhesive attached to the skin. For females, the bag is placed over the labia. Place a diaper over the infant (bag and all). Check your baby frequently and remove the bag after the infant has urinated into it. For active infants, this procedure may take a couple of attempts. Lively infants can displace the bag, causing an inability to obtain the specimen. The urine is drained into a container for transport back to the health care provider.
How to prepare for the test
A specimen container and instructions on cleansing and collection will be provided. If the collection is being taken from an infant, a couple of extra collection bags may be necessary.
How the test will feel
Rarely, infants may have a local skin reaction to the tape used with the collection bags.
Why the test is performed
The clean-catch method is used to avoid contaminating the urine sample with bacteria that are normally present in the urethra and appear in a voided urine sample. It is used for a routine urinalysis, a urine culture, or other urine tests that require uncontaminated urine for accurate results.
Normal values will depend on the specific test ordered, for example, urinalysis or urine culture.
What abnormal results mean
If the urine sample was sent for urinalysis, abnormal results may indicate the presence of white blood cells, red blood cells, or excessive amounts of protein.
If the urine sample was sent for urine culture, abnormal results may indicate excessive growth of bacteria a urinary tract infection or bladder infection.
What the risks are
No risks have been noted in collecting a clean catch urine sample.
This is a common method used to collect urine. A false negative urine culture may result from recent antibiotic use.
by Martin A. Harms, M.D.