--- title: "Leukocyte esterase levels: what a positive dipstick means, how it pairs with nitrite and microscopy, and the causes beyond a UTI" type: biomarker url: "https://www.test-well.com/biomarkers/leukocyte-esterase" also_known_as: - leukocyte esterase - leukocyte esterase, ua - leukocytes, urine - leukocytes in urine - wbc, urine - white blood cells, urine - le, ua - pyuria category: Urinalysis units: - WBC/hpf order_price_usd: 17.99 order_item: Complete Urinalysis Test order_url: "https://www.test-well.com/tests/urinalysis" reviewed_at: 2026-11-03 --- # Leukocyte esterase levels: what a positive dipstick means, how it pairs with nitrite and microscopy, and the causes beyond a UTI > Leukocyte Esterase is measured with a urine sample; no fasting is needed. At TestWell it's $17.99 all-in as Complete Urinalysis Test, results in 1–3 business days, drawn at Labcorp. An out-of-range result is a prompt to look closer, not a diagnosis. Leukocyte esterase is an enzyme carried by white blood cells, and a positive dipstick means white cells are in the urine — pyuria. With burning, frequency and a positive nitrite, it is a urinary tract infection; on its own it is a prompt to look at the microscopy, check for contamination, and consider the causes of white cells without bacteria, which range from a recently treated infection and sexually transmitted infections to kidney stones and, rarely, tuberculosis. Also known as: leukocyte esterase, leukocyte esterase, ua, leukocytes, urine, leukocytes in urine, wbc, urine, white blood cells, urine, le, ua, pyuria. ## Key facts | Fact | Value | | --- | --- | | Units | WBC/hpf | | Sample | Urine sample | | Fasting | Not required | | Results | 1–3 business days | | Price | $17.99 | | Labs | Labcorp · BioReference in NY/NJ | ## What does leukocyte esterase measure? Neutrophils — the white cells that respond to bacterial infection — carry esterase enzymes in their granules. When they enter the urine and break down, the enzyme is released, and the dipstick pad detects it. A positive pad therefore means white cells are, or recently were, in the urine, whether or not they are still intact enough to count under the microscope. Labs grade it trace to 3+. Microscopy confirms and counts: more than 5 white cells per high-power field in a centrifuged sample (or more than 10 per microliter in uncentrifuged urine) is pyuria. The dipstick catches roughly three-quarters to 95 percent of pyuria and is specific when it is clearly positive, so it is a reliable screen but not a diagnosis. The nitrite pad is its partner. Many gut bacteria that cause urinary infections — E. coli above all — convert the nitrate in urine to nitrite, given a few hours in the bladder. A positive nitrite is strong evidence of those bacteria; a negative nitrite rules out little, because Enterococcus, Staphylococcus saprophyticus, Pseudomonas and others do not make it, and a frequently emptied bladder gives them no time. Leukocyte esterase with nitrite and symptoms is a urinary infection; leukocyte esterase alone is a question. ## Who should check leukocyte esterase? Anyone with symptoms of a urinary infection — burning, urgency, frequency, lower abdominal pressure, cloudy or strong-smelling urine, blood in the urine — and anyone with flank pain, fever or chills that could be a kidney infection. Pregnant women are screened for bacteria in the urine at a first prenatal visit because untreated bacteriuria in pregnancy leads to kidney infection and preterm birth, and people about to have a urologic procedure are screened for the same reason. Outside those groups a positive result usually arrives on a routine urinalysis, and the right response is restraint: the IDSA guideline is explicit that white cells or bacteria in the urine of someone without symptoms (asymptomatic bacteriuria) should not be treated with antibiotics except in pregnancy and before urologic surgery, including in older adults, people with diabetes and people with catheters. Treating it does not help and breeds resistance. ## How to get tested for leukocyte esterase and prepare Leukocyte esterase is part of every complete urinalysis. Through TestWell the urinalysis with reflex to culture is the better order when infection is the question — if the dipstick or microscopy suggests infection the lab adds a urine culture automatically, which identifies the organism and its antibiotic sensitivities — and it is collected as a walk-in urine sample at Quest or Labcorp. The complete urinalysis without reflex is collected at Labcorp. Collect a clean-catch midstream sample: clean front to back, hold the labia apart or retract the foreskin, pass the first part into the toilet and catch the middle. A sample full of squamous epithelial cells is contaminated with vaginal or skin secretions, which carry white cells and are the most common false positive. A first-morning or several-hours-held sample gives nitrite its best chance. Large doses of vitamin C, high glucose or protein in the urine and very concentrated urine can mask the pad, and antibiotics already started will lower the count and sterilize the culture — collect before the first dose when you can. ## What is a normal leukocyte esterase result? Negative, with 0–5 white cells per high-power field on microscopy. Trace in a woman's sample with many squamous cells is usually contamination; 1+ or more, or more than 5 WBC/hpf on a clean sample, is pyuria and is interpreted with the nitrite, the bacteria count on microscopy, the symptoms and, when ordered, the culture. The combinations are the key to reading it: leukocyte esterase positive, nitrite positive and symptoms — a urinary infection, treat (a culture guides the choice if symptoms recur or in complicated cases); leukocyte esterase positive, nitrite negative, symptoms — probably still a urinary infection, culture to confirm because non-nitrite-forming organisms are common; both positive without symptoms — asymptomatic bacteriuria, not treated outside pregnancy or pre-procedure; leukocyte esterase positive with a negative culture — sterile pyuria, which has its own list of causes. ## What causes a positive leukocyte esterase? Urinary tract infection is the common cause — cystitis, pyelonephritis, prostatitis and urethritis — and contamination with vaginal secretions is the common false alarm. After those: a urinary infection treated in the past week or two (white cells outlast the bacteria), kidney and ureteral stones, interstitial cystitis, a urinary catheter, bladder tumors, recent cystoscopy or surgery, and radiation or chemotherapy (cyclophosphamide) cystitis. Sterile pyuria — white cells with a negative standard culture — points to sexually transmitted infections (chlamydia, gonorrhea, mycoplasma, trichomonas), genitourinary tuberculosis, fungal infection, partially treated infection, interstitial nephritis from drugs (NSAIDs, proton-pump inhibitors, antibiotics), inflammation next to the urinary tract (appendicitis, diverticulitis, pelvic inflammatory disease), kidney stones, Kawasaki disease in children, lupus nephritis and, in older men, prostatitis. Vaginitis and balanitis contribute white cells without any urinary infection at all. ## What to check next when leukocyte esterase is positive With urinary symptoms: a urine culture (or the reflex urinalysis), then treatment guided by local resistance patterns; recurrent infections, men, pregnancy, children, diabetes, catheters and any fever or flank pain make it a complicated infection that always gets a culture and sometimes imaging. Without symptoms: repeat on a properly collected midstream sample and, if the squamous cells have gone and the white cells remain, decide whether this is asymptomatic bacteriuria (leave it, outside pregnancy) or sterile pyuria. For sterile pyuria: nucleic-acid tests for chlamydia and gonorrhea, a review of recent antibiotics and NSAIDs, a repeat culture off antibiotics, a kidney ultrasound for stones and obstruction, creatinine and eGFR with a urine albumin-to-creatinine ratio for interstitial nephritis, and mycobacterial cultures when tuberculosis is plausible. Fever, rigors, flank pain, vomiting or confusion with pyuria means a kidney infection and same-day care. ## What does a high Leukocyte Esterase mean? Most often a urinary tract infection, especially with nitrites and symptoms; also vaginal contamination, kidney stones, interstitial cystitis, sexually transmitted infections and, with a negative culture, 'sterile pyuria' that includes tuberculosis and kidney inflammation. ## How do you get tested for Leukocyte Esterase? | Order | Type | Price | Includes | | --- | --- | --- | --- | | [Urinalysis, Complete](https://www.test-well.com/tests/urinalysis) | Single test | $17.99 | This marker | | [Kidney Health Panel](https://www.test-well.com/tests/kidney-health-panel) | Panel | $64.99 | 4 tests | | [Early Pregnancy Panel](https://www.test-well.com/tests/prenatal-screening-panel) | Panel | $249.99 | 9 tests | | [Men's Total Body Advanced Panel](https://www.test-well.com/tests/mens-total-body-advanced-panel) | Panel | $999.99 | 65 tests | | [Women's Total Body Advanced Panel](https://www.test-well.com/tests/womens-total-body-advanced-panel) | Panel | $999.99 | 65 tests | ## Quest vs Labcorp vs BioReference | Lab | Available | Price | Notes | | --- | --- | --- | --- | | Quest Diagnostics | No | — | Not offered through Quest for this test. | | Labcorp | Yes | $17.99 | Choose Labcorp at checkout; walk-in patient service centers in every state TestWell serves outside NY and NJ. | | BioReference (NY & NJ) | Yes | $20.99 | New York and New Jersey orders route here automatically — state rules keep Quest and Labcorp from accepting self-ordered draws. | - [What a high Leukocyte Esterase means (causes, symptoms, next steps)](https://www.test-well.com/biomarkers/leukocyte-esterase/high) ## Common questions about Leukocyte Esterase ### What does a positive leukocyte esterase mean? White blood cells are in the urine. With burning, frequency and a positive nitrite it is a urinary tract infection; with no symptoms it is most often contamination from vaginal secretions or asymptomatic bacteriuria, which is not treated outside pregnancy. White cells with a negative culture — sterile pyuria — prompt a look for sexually transmitted infections, stones, recent antibiotics, interstitial nephritis and, rarely, tuberculosis. ### Can you have a UTI with a negative nitrite? Yes. Nitrite only turns positive with bacteria that convert nitrate to nitrite — mainly E. coli and relatives — after several hours in the bladder. Enterococcus, Staphylococcus saprophyticus (common in young women) and Pseudomonas do not make nitrite, and frequent urination leaves no time for it. Leukocyte esterase positive with symptoms is treated as a likely infection and confirmed by culture. ### Should asymptomatic bacteria or white cells in urine be treated? Not in most people. The IDSA 2019 guideline recommends against screening for or treating asymptomatic bacteriuria in healthy women, older adults, people with diabetes, people with spinal cord injury or catheters, and kidney-transplant recipients beyond the first month, because antibiotics do not prevent harm and cause resistance and side effects. The exceptions are pregnancy and before urologic procedures that breach the mucosa. ### What is sterile pyuria? White cells in the urine when the standard bacterial culture grows nothing. Causes include a urinary infection treated in the past two weeks, chlamydia and gonorrhea, kidney stones, interstitial cystitis, interstitial nephritis from drugs, inflammation next to the bladder such as appendicitis, fungal infection and genitourinary tuberculosis. It is evaluated with sexually transmitted infection tests, a repeat culture off antibiotics, kidney function and imaging. ### Do I need a doctor's order to test my leukocyte esterase? No. TestWell's licensed physician network reviews and approves your order — usually within minutes. You can place an order online without an in-person visit or a referral from your own doctor. ### How long does it take to get Leukocyte Esterase results? Most Leukocyte Esterase results are available in 1–3 business days after your specimen arrives at the lab. You'll get an email the moment your results are ready, with everything viewable in your TestWell portal. ### How much does a Leukocyte Esterase test cost? Our Complete Urinalysis Test starts at $17.99. That's the all-in price — no copays, no insurance hoops, no surprise bills. HSA and FSA cards are accepted. ### Do I need to fast before my Leukocyte Esterase test? Fasting is not required for the Leukocyte Esterase test. You can have your blood drawn any time of day. ### Which lab will process my Leukocyte Esterase test? Your test will be processed by Quest Diagnostics, Labcorp, or BioReference depending on which is closest to you and which lab carries the test. All three are CLIA-certified and trusted by hospitals nationwide. You'll choose your lab during checkout from 4,000+ locations. ## Keep reading - [How to Read Your Blood Test Results, Line by Line](https://www.test-well.com/guides/how-to-read-your-blood-test-results) - [Metabolic Lab Testing: Which Panel Do You Actually Need?](https://www.test-well.com/guides/metabolic-lab-testing) - [Frequent urination: which blood tests?](https://www.test-well.com/symptoms/frequent-urination) - [Fatigue: which blood tests?](https://www.test-well.com/symptoms/fatigue) - [Before your test: Antibiotics](https://www.test-well.com/prep/antibiotics) - [Before your test: Vitamins and supplements (when to stop)](https://www.test-well.com/prep/vitamins-and-supplements) - [Before your test: Hydration](https://www.test-well.com/prep/hydration) ## Sources - [MedlinePlus (NIH) — Urinalysis](https://medlineplus.gov/lab-tests/urinalysis/) - [Simerville JA, et al. Urinalysis: a comprehensive review. Am Fam Physician. 2005;71(6):1153–62](https://www.aafp.org/pubs/afp/issues/2005/0315/p1153.html) - [Nicolle LE, et al. IDSA clinical practice guideline for the management of asymptomatic bacteriuria: 2019 update. Clin Infect Dis. 2019;68(10):e83–e110](https://pubmed.ncbi.nlm.nih.gov/30895288/) - [Wise GJ, Schlegel PN. Sterile pyuria. N Engl J Med. 2015;372(11):1048–54](https://pubmed.ncbi.nlm.nih.gov/25760357/) ## Related biomarkers - [Protein in Urine](https://www.test-well.com/biomarkers/protein-in-urine) - [Blood in Urine](https://www.test-well.com/biomarkers/blood-in-urine) - [Ketones in Urine](https://www.test-well.com/biomarkers/ketones-in-urine) - [Urobilinogen](https://www.test-well.com/biomarkers/urobilinogen) - [Bilirubin in Urine](https://www.test-well.com/biomarkers/bilirubin-in-urine) - [Epithelial Cells in Urine](https://www.test-well.com/biomarkers/epithelial-cells-in-urine) - [Reference range lookup tool](https://www.test-well.com/tools/reference-range-lookup) - [Lab unit converter](https://www.test-well.com/tools/lab-unit-converter) - [All biomarkers](https://www.test-well.com/biomarkers) --- Medically reviewed by Youmna DiStefano, MD (Medical Reviewer, TestWell); last reviewed 2026-11-03. Review policy: https://www.test-well.com/reviewers/youmna-distefano-md Canonical page: https://www.test-well.com/biomarkers/leukocyte-esterase Machine-readable catalog: https://www.test-well.com/api/catalog.json · MCP server: https://www.test-well.com/mcp · Overview for agents: https://www.test-well.com/llms.txt Prices are cash-pay, in USD, and include physician authorization; every order adds one flat $6 lab processing fee. Educational content is not a diagnosis — discuss results with a clinician.