What It Is
A urine culture is a laboratory test used to detect and identify bacteria present in the urine, helping confirm and characterize a urinary tract infection.
What It Checks
A urine culture identifies whether bacteria are present in a urine sample in significant amounts, and if so, helps identify the specific type of bacteria responsible. Further testing on a positive culture can also determine which antibiotics are likely to be effective against that specific bacteria.
Why It's Used
A urine culture is commonly used to confirm a suspected urinary tract infection, particularly when symptoms are present, and to help guide the choice of antibiotic treatment based on the specific bacteria identified and its sensitivity pattern.
How It's Done
A urine culture requires a urine sample, generally collected using a technique designed to minimize contamination from surrounding skin or other sources. In the laboratory, a small amount of the sample is placed onto a culture medium, which supports bacterial growth, and the sample is incubated for a period, typically one to two days, while laboratory staff monitor for and then identify any bacterial growth that occurs.
Background
Urine culture techniques developed alongside the broader growth of microbiology in the late 19th and early 20th centuries, building on general advances in growing and identifying bacteria in laboratory settings. Standardized methods for counting bacterial growth to distinguish a true infection from incidental contamination were developed further over the 20th century, and urine culture remains the standard method for confirming and characterizing urinary tract infections today.