Leukocyte Esterase in Urine: What a Positive Result Means
Also known as: Leukocyte esterase in urine, leukocytes esterase, LE urine test
Leukocyte esterase is an enzyme released by white blood cells, so its presence on a urine dipstick suggests white blood cells (and possibly infection) in the urine. A normal result is negative; a positive result (often reported as trace, 1+, 2+, or 3+) commonly suggests a urinary tract infection but needs to be confirmed with a urine culture or microscopic exam, since other conditions can also cause it. Results are always interpreted by a clinician alongside your symptoms and the rest of the urinalysis.
Leukocyte Esterase normal range
| Category | Range (qualitative (negative/trace/1+/2+/3+)) |
|---|---|
| Negative (normal) | NegativeNo significant white blood cells detected |
| Trace | Trace positiveBorderline; often repeated or correlated with symptoms |
| Positive | 1+ to 3+Higher grades suggest more white blood cells |
Reference ranges vary by laboratory. Use the range printed on your own report as the definitive comparison.
What high Leukocyte Esterase can mean
- Urinary tract infection (the most common cause of a positive result)
- Kidney infection (pyelonephritis) if accompanied by fever or flank pain
- Inflammation of the urinary tract without infection (sterile pyuria)
- Contamination of the sample, especially in women, from vaginal discharge
What low Leukocyte Esterase can mean
- A negative result is the normal, expected finding
- A negative result doesn't completely rule out a urinary tract infection, especially early or mild cases
What to do about an abnormal result
- A positive leukocyte esterase is a screening clue, not a diagnosis — it's usually confirmed with a urine culture and, often, the nitrite result and microscopic exam.
- Tell your doctor about symptoms like burning with urination, urgency, frequency, or fever, which help interpret the result.
- If you have a fever, back pain, nausea, or vomiting along with a positive result, seek medical care promptly, since this can suggest a kidney infection.
- Don't self-diagnose or start antibiotics from a dipstick result alone — a clinician interprets it alongside your symptoms and other urinalysis findings.
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Frequently asked questions
What does positive leukocyte esterase mean?
A positive leukocyte esterase result means white blood cells are likely present in your urine, which most often suggests a urinary tract infection. It's a screening finding rather than a confirmed diagnosis, so doctors typically pair it with a urine culture, the nitrite result, and your symptoms before starting treatment.
Can leukocyte esterase be positive without an infection?
Yes. A positive leukocyte esterase can occur from sample contamination (especially in women, from vaginal discharge), inflammation of the urinary tract without active infection (sometimes called sterile pyuria), or other irritation. That's why a positive dipstick result is usually confirmed with a urine culture rather than treated as a definite infection on its own.
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Medically reviewed by Antonieta Rueda, MD and Kyle R. Toth, MD · Last reviewed July 6, 2026
This article is for informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or your lab results.