Urine Culture Test: Purpose, Procedure, Normal Range, Results & Uses

Urine Culture Test: Purpose, Procedure, Results & Everything You Need to Know

A urine culture test is a laboratory test to look for bacteria, fungi, or other microorganisms in the urine. It is among the gold standard confirmatory test for diagnosing bacterial urinary tract infection (UTI) and the specific organism responsible for the infection. Unlike a routine urine test, a culture examination of urine can diagnose the infection and determine which organism is causing it.

The test is often performed as a urine culture and sensitivity test to determine which antibiotics will be effective against the bacteria present.

In this article, we discuss what a urine culture test is, how to read the urine culture report, and the expected results for a urine culture test.

Quick Highlights

What is a Urine Culture Test?

While urinalysis detects issues like white blood cells, protein, blood, sugar, or crystals, a culture examination of urine is used to confirm whether an infection is present and to determine the cause. Thus, it is the gold standard for diagnosing bacterial UTI.

The test is typically done along with a urine culture and sensitivity test. If bacteria are found, they are tested against various antibiotics to determine which medicine will treat the infection. That way, doctors won't overuse ineffective antibiotics.

So what does a urine culture detect?  The test is often used to check for:

• Escherichia coli (E. coli), which is most frequently responsible for UTIs
• Klebsiella species
• Proteus species
• Enterococcus species
• Pseudomonas aeruginosa
• Staphylococcus saprophyticus
• Candida species (yeast infections)

The test is not used for the diagnosis of kidney stones, bladder cancer, viral infections or most sexually transmitted infections. If these conditions are suspected, further investigations will be needed.

Why is the Urine Culture Test Done?

Doctors recommend a urine culture test for the diagnosis of a urinary infection and to plan treatment accordingly. A culture sensitivity test of urine is very helpful when symptoms continue to persist despite treatment or in case of recurrent infections.

The test may be prescribed for:

• Diagnosing a UTI
• Identifying bacteria causing infection
• Selecting the most effective antibiotic
• Keep track of recurrent urinary infections
• Assessing ongoing urinary symptoms
• Asymptomatic bacteriuria diagnosis during pregnancy
• Assessing infections before urological surgery
• Monitoring for response to continued antibiotic treatment
• Investigating unexplained fever in some patients

The test is also advised for people who have kidney disease, diabetes, urinary catheters, or an enlarged prostate gland. They are also recommended to those with structural abnormalities of the urinary tract, because these have an increased risk of complicated infection.

Symptoms or Conditions That Need This Test

If you have symptoms typical of a UTI, you might need a culture sensitivity urine test to diagnose the infection.

Common symptoms include:

• Burning while passing urine
• Pain during urination
• Frequent urination
• An urgent need to urinate.
• Having to clear small amounts of urine often
• Cloudy urine
• Blood in urine
• Foul-smelling urine
• Abdominal pain in the lower part
• Pelvic discomfort
• Fever with chills
• Back or flank pain
• Kidney infection with nausea and vomiting

It may also be recommended for pregnant women, for patients who are having procedures done on the kidneys and bladder, or for people with lower resistance to infection.

How is the Urine Culture Test Performed?

The urine cs test is quick, easy and is typically completed in a few minutes.  The accuracy of the results can be compromised by sample contamination, so proper sample collection is important.

Typically, the process involves:

1. Wash hands well and thoroughly.
2. Use clean, sterile wipes to clean the genitals.
3. Start urinating into the toilet.
4. Collect the midstream urine in a sterile container.
5. Avoid touching the inside of the container.
6. Seal the container as soon as possible.
7. Take the sample to the lab within 1-2 hours.

Sometimes urine is collected by a urinary catheter in infants, hospitalised persons, or people who are unable to get a clean sample. In very special circumstances, a sterile needle can be inserted directly into the bladder to extract urine.

After the sample is taken, urine undergoes a culture examination of urine where a sample of urine is placed on culture media. Plates are incubated for 24–48 hours to permit microorganisms to develop.

When bacterial colonies are discovered, further tests are conducted to determine the type of bacteria and its antibiotic sensitivity. The urine culture and sensitivity test is completed in 24-72 hours, depending on the microorganism identified.

Preparation Before the Test

Proper preparation can enhance the accuracy of the urine culture test.

Your doctor may advise you to:

• Let the lab know if you take any antibiotic drugs.
• Refrain from administering antibiotics before the sample is taken, unless medically necessary.
• Have regular amounts of water.
• Should limit excessive fluid intake immediately before collection since this might dilute the sample.
• Thoroughly wash the genital area before urine is collected.
• Obtain a midstream clean urine specimen.
• Use a laboratory-supplied sterile container.
• Turn in the sample promptly.

Women should notify their physician if they are menstruating, as the menstrual blood may contaminate the specimen.

Urine Culture Test Normal Values / Expected Results

The urine culture test normal values are based on the growth of bacteria rather than a numerical range. If no disease-causing microorganisms appear in the culture after the incubation period is over, the result is considered to be a normal report, but clinical correlation is still essential, especially if symptoms persist.

Bacterial counts of ≥100,000 colony-forming units (CFU) per millilitre (mL) of properly collected midstream urine are considered significant. Certain patients with symptoms, children, catheterised persons or women who are pregnant, however, may have lower counts of bacteria and still be infected.

Results Interpretation

A urine culture report gives important information whether microorganisms are present in the urine sample and if there is, which microorganism is responsible for the infection.  If significant bacterial presence is detected, the report will also include antibiotic susceptibility testing results.

Some variations in format may occur between laboratories, but most reports will include the same information.

Components of a Urine Culture Report

The urine culture report should always be based on the symptoms, medical history, and physical exam. A positive culture isn't always a sign of an active infection, particularly if you're not experiencing symptoms.

Meaning of a Positive Urine Culture Test

A positive urine culture test means that bacteria or fungi have been detected in the urine sample. This indicates that there are microorganisms in the urinary tract that may be responsible for an infection.

A positive report can mean:

• Infection in the urinary system (UTI)
• Bladder infection (cystitis)
• Kidney infection (pyelonephritis)
• Urinary tract infections that are associated with the use of a catheter.
• Asymptomatic bacteriuria, especially during pregnancy

When one type of bacteria grows considerably, it is more likely to represent a true infection.

However, if multiple organisms are found, contamination during sample collection may have occurred. In these situations, your physician might suggest repeating the test.

The accompanying culture sensitivity urine test shows which antibiotics will work on the bacteria and which ones they are resistant to.

What Does "No Growth" Mean?

When a report states "No Growth", it indicates that there were no disease-causing bacteria or fungi present during the incubation period.

This generally indicates:

• No bacterial urinary tract infection
• Effective cure of prior infection
• Symptoms resulting from a non-bacterial condition

If urine symptoms persist but the test comes back as 'No Growth', your doctor may order other tests to explore other potential causes.

Understanding the Urine Culture and Sensitivity Test

When urinary bacteria reproduce in the urine culture, a urine culture and sensitivity test is typically carried out.

The "sensitivity" section of the test indicates which antibiotics work against the identified bacteria.

The results are usually expressed as:

• Sensitive (S):The antibiotic should cure the infection.
• Intermediate (I):The antibiotic may work under specific conditions or at higher doses.
• Resistant (R):The antibiotic is not likely to work against the bacteria.

For example:

Health care providers use this information to select appropriate treatment and minimise unnecessary antibiotic use.

Risks or Side Effects

A urine culture test is a simple collection of a urine sample and has minimal risks involved.

Possible issues include:

• Slight difficulty in sample collection
• Sample contamination if proper instructions are not followed
• Retest if the specimen is contaminated
• Minimal discomfort for obtaining a sample from a catheter if necessary

Benefits of the Test

The culture examination of urine has the following clinical advantages:

• Early recognition of UTIs
• Correct identification of disease-causing microorganisms
• Appropriate selection of antibiotic therapy
• Lower chance of antibiotic resistance
• Improved treatment outcomes
• Improve monitoring of recurrent infections
• Prevention of complications like kidney infections
• Support with infection management in pregnancy
• Useful prior to some urological surgeries

The test determines the specific type of infection, enabling more accurate and effective treatment by the doctor.

Who Should Get This Test?

A urine culture test may be recommended for:

• Adults who have symptoms of UTIs
• Pregnant women
• Children with unexplained fever
• Urinary symptoms in older adults
• Women who have had multiple UTIs
• People with diabetes
• Patients with kidney disorders
• People who have compromised immune systems
• Patients with urinary catheters
• Individuals who are undergoing urological procedures

Tests may also be ordered after the antibiotics have been completed, when symptoms remain or return.

Urine Culture Test Price in India

The urine culture test price depends on the laboratory, city, accreditation, and whether the test is ordered with antibiotic susceptibility testing. The urine culture test cost in India varies from an average of ₹300 to ₹1,000.

Slightly more expensive rates may apply to premium laboratories or home sample collection.

Approximate City-wise Pricing

This is an estimated price and may differ from laboratory to laboratory, home collection services and local healthcare costs.

Factors Affecting the Urine Culture Test Cost

The urine culture test cost can differ according to:

• The type of diagnostic laboratory
• NABL accreditation
• Home sample collection
• Inclusion of antibiotic sensitivity testing
• City and location
• Promotional discounts
• Report turnaround time

Does Health Insurance Cover It?

A urine culture test might be included in a health insurance plan if it is required for medical reasons and ordered by a licensed health care provider.

Coverage will vary based on several factors, such as:

• Conditions and terms of policy
• Hospitalization status
• Outpatient (OPD) benefits where applicable
• Medical necessity
• Insurer guidelines

It is important for patients to check their policy details or contact their insurer to find out what is covered and what is not.

Reader Information: The information provided in this article is for general educational and informational purposes only. It is not intended to replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider or doctor for proper evaluation and guidance regarding your health condition or test results.