From the Guidelines
A urine culture test is a diagnostic procedure that identifies bacteria or other microorganisms in the urine that may be causing a urinary tract infection (UTI), and it is considered the current reference standard for confirming the etiologic pathogen in patients with suspected infection, as stated in the 2024 guidelines for the prevention, diagnosis, and management of urinary tract infections in pediatrics and adults 1.
Key Points About Urine Culture Tests
- The test involves collecting a clean-catch midstream urine sample, which is then placed in a special container with nutrients that allow bacteria to grow.
- Laboratory technicians observe the sample for 24-48 hours to see if any bacteria develop and, if so, identify the specific type and determine which antibiotics will be most effective for treatment.
- This test is typically ordered when a patient shows symptoms of a UTI such as painful urination, frequent urination, cloudy urine, or lower abdominal pain.
- It's also used to confirm UTIs when a urinalysis shows signs of infection, to identify the specific pathogen causing recurrent infections, or to ensure an infection has been successfully treated.
Importance of Proper Collection Techniques
- For accurate results, patients should clean the genital area before collection, start urinating into the toilet, then collect the middle portion of urine in the sterile container provided, avoiding touching the inside of the container.
- The sample should be delivered to the laboratory within one hour or refrigerated if there will be a delay, as noted in the 2003 clinical policy for children younger than three years presenting to the emergency department with fever 1.
Interpretation of Urine Culture Results
- Urine culture results are considered positive or negative on the basis of the number of CFUs that grow on the culture medium, with a threshold of at least 50 000 CFUs per mL of a single urinary pathogen considered significant in infants and children, as stated in the 2011 urinary tract infection clinical practice guideline for the diagnosis and management of the initial UTI in febrile infants and children 2 to 24 months 1.
- The interpretation of urine culture results must take into account the clinical presentation, any history of urinary tract infection or urinary tract abnormalities, previous antibiotic use, and the presence of pyuria and bacteriuria.
From the Research
Definition of Urine Culture Test
- A urine culture test is a laboratory test used to diagnose urinary tract infections (UTIs) by detecting the presence of microorganisms in a urine sample 2, 3, 4, 5, 6.
- The test involves collecting a urine sample and analyzing it for the presence of bacteria, yeast, or other microorganisms that can cause UTIs.
Purpose of Urine Culture Test
- The primary purpose of a urine culture test is to identify the type of microorganism causing the UTI and to determine the appropriate antibiotic treatment 2, 3, 5.
- The test can also help to distinguish between a UTI and other conditions that may cause similar symptoms.
How Urine Culture Test is Performed
- A urine culture test typically involves collecting a midstream urine sample, which is then sent to a laboratory for analysis 3, 4, 6.
- The laboratory will then incubate the urine sample to allow any microorganisms present to grow, and will identify the type of microorganism and its antibiotic susceptibility.
Interpretation of Urine Culture Test Results
- The results of a urine culture test are typically reported as the number of colony-forming units (CFU) of microorganisms per milliliter (mL) of urine 3, 4.
- A positive result indicates the presence of a UTI, while a negative result indicates that no microorganisms were detected in the urine sample.
- The results of the test can also be used to guide antibiotic treatment and to monitor the effectiveness of treatment 2, 5.