UrinalysisNo Fasting RequiredTurnaround: 24–48 hours (bacterial incubation & susceptibility)

Urine Culture & Sensitivity (Urine C/S & Antibiogram)

Also known as: Urine C/S, Bacterial Urine Culture, Urine Sensitivity Test, Antibiogram, Urine C&S

Parameters Measured in the Report

A breakdown of individual biomarkers and biological reference intervals typically found in your report:

Biomarker	Standard Range	Unit	What It Means
Colony Count (Quantitative Colony Count)	No Growth (< 1,000 CFU/mL) Clinically Significant Infection: ≥ 100,000 CFU/mL	CFU/mL (Colony Forming Units)	Quantity of bacteria grown; ≥100,000 CFU/mL of a single uropathogen confirms active acute cystitis.
Uropathogen Identification (Bacterial Species)	Sterile / No Pathogenic Growth	species	Specific bacterial organism identified (e.g., Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterococcus).
Antibiotic Sensitivity Profile (Antibiogram)	Susceptible (S) to First-Line Regimens	susceptibility (MIC)	Minimum Inhibitory Concentration (MIC) testing determining which antibiotics effectively inhibit the bacterial strain.

* Note: Reference ranges may vary slightly between testing instruments and reagent kits. Always refer to the reference interval printed on your specific pathology report.

Clinical Focus

Viable bacterial colony count (CFU/mL), identification of specific uropathogen species, and antibiotic susceptibility profile (MIC antibiogram).

Sample & Specimen

Clean-catch midstream urine in sterile universal container

Fasting Protocol

No fasting required. Collect prior to initiating antibiotic therapy whenever clinically possible.

Turnaround Time

24–48 hours (bacterial incubation & susceptibility)

What Is This Test?

Urine Culture and Sensitivity (Urine C/S) is the definitive microbiological gold-standard test used to diagnose active bacterial urinary tract infections. While a routine dipstick or microscopic urinalysis can reveal signs of inflammation (pus cells or nitrites), it cannot identify the exact offending bacterial species or predict which medication will kill it. In the microbiology laboratory, a measured loop of urine is streaked onto selective agar culture plates (such as CLED or MacConkey agar) and incubated at 37°C for 24 to 48 hours. If bacteria grow into colonies exceeding the clinical threshold (typically ≥ 100,000 CFU/mL of a single organism), the pathogen is identified (most commonly Escherichia coli, Klebsiella pneumoniae, or Enterococcus faecalis), and an automated Antibiogram is performed to report which antibiotics are Susceptible (S), Intermediate (I), or Resistant (R).

Why Did Your Doctor Order This Test?

Physicians routinely prescribe the Urine Culture (C/S) in the following clinical scenarios:

Symptoms of acute urinary tract infection: severe burning with urination (dysuria), urinary frequency, urgency, suprapubic pain, or cloudy foul-smelling urine

Suspected upper urinary tract infection / acute pyelonephritis (kidney infection): high fever, chills, nausea, and severe flank or back tenderness

Recurrent, complicated, or treatment-refractory UTIs that fail to improve after standard empirical antibiotics

Routine prenatal screening for Asymptomatic Bacteriuria in pregnant women (to prevent pre-term labor and pyelonephritis)

Pre-urological surgical evaluation to ensure sterile urine before catheterization, cystoscopy, or prostate resection

How to Prepare Before Your Test

Fasting Requirement: No fasting required. Collect prior to initiating antibiotic therapy whenever clinically possible.

Collect a "Clean-Catch Midstream" specimen: wash hands, cleanse the urethral opening, urinate into the toilet for 2 seconds, and collect the mid-portion directly into the sterile cup.
Specimen must be collected BEFORE starting oral or IV antibiotics; taking even a single dose of an antibiotic can inhibit bacterial growth on culture plates, causing false-negative results.
Deliver the specimen to the laboratory within 1 to 2 hours of collection, or keep refrigerated at 4°C if transport is delayed (to prevent room-temperature bacterial overgrowth).

Understanding Your Results

What higher or lower readings generally mean in clinical practice:

If Values Are Higher Than Normal

Growth of ≥100,000 CFU/mL of a single organism confirms an active bacterial Urinary Tract Infection (UTI). The attending physician uses the antibiogram to prescribe the narrowest-spectrum oral antibiotic that is reported as "Susceptible (S)" (such as nitrofurantoin, fosfomycin, cefixime, or trimethoprim-sulfamethoxazole), preventing treatment failure and antibiotic resistance.

If Values Are Lower Than Normal

A report of "No growth after 48 hours of incubation" is healthy and reassuring, confirming that the bladder urine is sterile and that urinary symptoms may stem from non-bacterial irritation, interstitial cystitis, or viral urethritis.

Frequently Asked Questions

Why does a urine culture take 24 to 48 hours when a urine routine test is ready in 1 hour?

A urine routine uses chemical dipsticks and a microscope to count cells today. A urine culture requires living bacteria to incubate, divide, and multiply into physical colonies overnight on nutrient agar plates, and then undergo another 24 hours of antibiotic exposure testing.

What does "Mixed Bacterial Flora" or "Contaminated Sample" mean on a culture report?

If three or more different bacterial species grow in low numbers, it means normal bacteria from the skin and external genitalia contaminated the cup during collection. The test is inconclusive and must be repeated with a proper clean-catch midstream sample.

Related Laboratory Tests

Tests frequently prescribed together or used as follow-up investigations:

Urine Routine & Microscopic Examination (Urine R/M)

Physical properties (color, clarity, specific gravity), chemical dipstick (protein, glucose, nitrites), and microscopic sediment.

Urine Microalbumin / Albumin-to-Creatinine Ratio (UACR)

Microscopic leakage of albumin protein standardized against urine creatinine excretion.

Complete Blood Count (CBC / Hemogram)

Counts and evaluates red blood cells, white blood cells, hemoglobin, hematocrit, and platelets.

Medical & Diagnostic Disclaimer

This guide is published for educational and patient informational purposes only. It is not a substitute for professional medical evaluation, diagnosis, or clinical advice.

A laboratory result that falls slightly outside standard statistical reference intervals does not automatically indicate disease; conversely, a normal result does not guarantee the absence of medical conditions. Only your attending physician can interpret lab findings in the context of your medical history, physical exam, and symptoms.