When a urine test indicates “mixed flora,” it often raises questions about a possible infection. This common finding can be confusing for those unfamiliar with laboratory terms. Understanding what “mixed flora” means in a urine sample is important for accurately interpreting health information.
Understanding “Mixed Flora” in Urine
“Mixed flora” in a urine sample refers to the presence of multiple types of microorganisms, primarily bacteria. The urinary tract, including the bladder and kidneys, is typically sterile. However, the external genital area and skin surrounding the urethra naturally harbor a diverse community of bacteria, known as normal flora.
During urine sample collection, these external bacteria can easily enter the collection cup, leading to sample contamination. This contamination is a frequent reason for a “mixed flora” result. The presence of these multiple bacterial types in a sample does not automatically mean there is an infection within the urinary tract. Instead, it often suggests that bacteria from the skin or genital region have inadvertently made their way into the sample during collection.
Is “Mixed Flora” Always an Infection?
“Mixed flora” in urine is frequently not an infection within the urinary tract. The most common reason for this finding is contamination of the urine sample during collection, where bacteria from the skin or vagina enter the sample. When multiple bacterial species appear in relatively equal numbers on a culture, without one predominant type, it strongly suggests contamination rather than an infection.
Another possibility is asymptomatic bacteriuria, which is the presence of bacteria in the urinary tract without any symptoms of an infection. This condition is common in certain populations and usually does not require antibiotic treatment.
A true urinary tract infection (UTI) typically involves a significant amount of one or, less commonly, two predominant types of bacteria, along with noticeable symptoms. These include painful urination, frequent urges to urinate, or lower abdominal discomfort. Without such symptoms, a “mixed flora” result is more likely due to contamination or harmless colonization.
When “Mixed Flora” May Indicate a Problem
“Mixed flora” can sometimes warrant further investigation. If the “mixed flora” result is accompanied by classic UTI symptoms, such as painful urination, increased frequency, urgency, or lower abdominal pain, it suggests a possible infection that requires further evaluation. If these symptoms are present, it implies an underlying issue that needs attention.
In certain patient populations, even asymptomatic mixed flora might be considered more significant. This includes pregnant individuals, immunocompromised patients, or those with indwelling catheters. For pregnant women, asymptomatic bacteriuria is screened for and often treated due to potential complications like pyelonephritis or preterm labor. Similarly, in catheterized patients, mixed flora could represent a true polymicrobial infection.
If “mixed flora” is consistently found in multiple urine samples despite proper collection techniques, it could suggest persistent colonization or an atypical infection. In such cases, a healthcare professional might explore other potential underlying urogenital health issues or consider more advanced testing.
Next Steps and Proper Sample Collection
If you receive a “mixed flora” result, consulting a healthcare professional is important. Only a doctor can properly interpret the results in the context of your symptoms and medical history. They will consider all factors to determine if the finding is due to contamination, colonization, or a true infection.
To minimize contamination and ensure accurate results, collecting a proper “clean catch” midstream urine sample is important. This method involves several steps:
Wash your hands thoroughly.
Cleanse the genital area with provided wipes – for females, separating the labia and wiping from front to back; for males, cleaning the tip of the penis.
Begin urinating a small amount into the toilet to flush out any bacteria from the urethra’s opening.
Without stopping the flow, place the collection cup into the stream to collect the “midstream” portion of urine, filling it approximately halfway.
Finish urinating into the toilet and secure the lid on the cup.
Your doctor might recommend a repeat urine test with another clean catch sample if the initial one was likely contaminated. They may also order a urine culture to identify specific bacteria and their antibiotic susceptibility, or other diagnostic tests if an infection is suspected based on your symptoms.