Guides
What Do Leukocytes in the Urine Mean? Is It Always an Infection?
Leukocytes in the urine are not always an infection. Contamination, stones and sexually transmitted infections can also cause them; if there are no symptoms, antibiotics are usually not needed.
Translated from the Turkish original by DoktorClub. The Turkish version is the reference text; this English translation has not been separately reviewed by a physician. Read the Turkish original.
Key takeaway
White blood cells (leukocytes) in the urine (pyuria) indicate inflammation in the urinary tract; but this does not always mean infection. Contamination of the sample, stones, and vaginal or sexually transmitted infections can also cause leukocytes. According to the European Association of Urology (EAU) 2026 and Infectious Diseases Society of America (IDSA) 2019 guidelines, asymptomatic bacteriuria is generally not treated. The exceptions are pregnancy and certain procedures to be performed on the urinary tract. Evaluate your result according to the laboratory reference range on your report.
Short Answer
White blood cells (leukocytes) in the urine (pyuria) indicate inflammation in the urinary tract; but this does not always mean infection. Contamination of the sample, stones, and vaginal or sexually transmitted infections can also cause leukocytes. According to the European Association of Urology (EAU) 2026 and Infectious Diseases Society of America (IDSA) 2019 guidelines, asymptomatic bacteriuria is generally not treated. The exceptions are pregnancy and certain procedures to be performed on the urinary tract. Evaluate your result according to the laboratory reference range on your report.
How does it appear on your report?
- Strip (dipstick) section: Listed as "Lökosit esteraz" (leukocyte esterase), "LEU" or "Lök". The result is written in grades as "negative", "trace" or with plus (+) signs.
- Microscopy (sediment) section: The "Lökosit" (leukocyte) line is given as a count per high-power field (/HPF) or per microliter (/µL). The unit and reference range vary by analyzer.
- Adjacent lines: The nitrite, bacteria, red blood cell and squamous epithelial cell lines are important for interpreting leukocytes.
- e-Nabız (Türkiye's national health record app): In the "Tahlillerim" (My Test Results) section, the result is listed together with its reference value. Values outside the reference range are shown in color.
- Decision limit: According to the Ministry's decision limit procedure, decision limits are marked with an asterisk (*) on the report and explained at the bottom of the report. In microbiology tests, the decision limit is the threshold set by the company that manufactures the test.
Normal values and reference range
| Method | Value considered pyuria | Source |
|---|---|---|
| Counting chamber in uncentrifuged urine | ≥10 leukocytes/µL | KLİMUD 2020 |
| Uncentrifuged urine, 40x objective | ≥3 leukocytes in every field | KLİMUD 2020 |
| Gram stain, 100x objective | At least 1 leukocyte in every field | KLİMUD 2020 |
| Strip leukocyte esterase | Positive | KLİMUD 2020 |
| UK primary care threshold | >10⁴ leukocytes/mL (>10⁷/L) | UKHSA 2025 |
For centrifuged sediment, the laboratory sets the range. Go by the range on your report.
A reference range covers 95% of healthy people; about 1 in 20 healthy people may fall slightly outside the range. For this reason, a single mild elevation does not by itself indicate a disease.
What does it mean if it is high?
The causes are listed from common and harmless to serious.
- Contamination of the sample: Collecting the first part of the urine in the container or mixing in vaginal discharge increases leukocytes. Plenty of squamous epithelial cells may suggest contamination, but this alone is not considered proof.
- Asymptomatic bacteriuria: There are bacteria in the urine but no complaints. Leukocytes may also accompany this condition. According to EAU 2026, its frequency is 1–5% in healthy premenopausal women and 15–50% in older adults in care homes.
- Urinary tract infection (cystitis): Accompanied by burning on urination and frequent, urgent urination. According to the EAU, the diagnosis is based mainly on these complaints and the absence of vaginal discharge.
- Genital and sexually transmitted infections: Chlamydia and gonorrhea can cause leukocytes without growth in culture. The UK health authority (UKHSA) recommends considering chlamydia, especially at ages 16–24.
- Stones, catheters and recent antibiotics: These situations can also cause culture-negative leukocytes.
- Kidney infection (pyelonephritis): Occurs with fever, chills and flank pain; same-day assessment is needed.
- Less common causes: Kidney tuberculosis, papillary necrosis, bladder tumors and some kidney diseases. The KLİMUD guideline also lists diabetes and cancer among the causes of pyuria.
Are antibiotics needed if there are no symptoms? Usually not. According to IDSA 2019, asymptomatic bacteriuria is defined regardless of whether there are leukocytes in the urine. The guideline does not recommend screening and treatment for healthy non-pregnant women, people with diabetes, and older adults in care homes. EAU 2026 also states that in catheterized patients, leukocytes accompanying bacteriuria are not by themselves a reason for antibiotics.
There are two important exceptions:
- Pregnancy: IDSA and EAU recommend screening for and treating asymptomatic bacteriuria in pregnancy.
- Before a urological procedure that damages the mucosa: Screening and treatment are recommended before endoscopic urinary tract procedures.
When read together
- Leukocytes positive + nitrite positive + complaints present: A urinary tract infection is likely. According to UKHSA, a positive nitrite, or leukocytes and blood both being positive, makes infection likely.
- Leukocytes positive + nitrite negative: According to UKHSA, infection and another cause are equally likely. For nitrite to form, urine must stay in the bladder for at least 2 hours; a negative result does not rule out infection.
- Leukocytes positive + plenty of squamous epithelial cells: The sample may be contaminated. A new sample using the clean midstream method may be requested.
- Leukocytes positive + no growth in culture (sterile pyuria): Recent antibiotics, chlamydia, stones or tuberculosis come to mind. This situation may require further investigation.
- Leukocytes + red blood cells + flank pain: Evaluated for stones or kidney infection.
- Leukocytes + protein: Infection can temporarily increase protein in the urine. Protein is rechecked after the infection has passed.
Preparing for the test
- The right time: First morning urine, or urine that has stayed in the bladder for at least 2 hours, is preferred. Do not drink extra water to speed up urination.
- Midstream method: Pass the first part of the urine into the toilet and collect the middle part in the container. The Ministry's Total Testing Process Guideline states that midstream urine is valuable for bladder diseases.
- Cleaning: Wash your hands. Women should separate the labia and clean from front to back. Do not wipe the genital area with antiseptic or disinfectant; it can affect the result.
- Delivery time: According to KLİMUD, if the sample cannot reach the laboratory within 1 hour, it can be kept in the refrigerator for up to 24 hours. Urine samples are not frozen.
- Before antibiotics: If a culture will be ordered, give the sample before starting antibiotics.
- Menstrual period: Because blood and discharge may mix in, postpone the test if possible or tell the laboratory.
- Over 65: UKHSA recommends not using urine dipsticks in this age group because asymptomatic bacteriuria is common.
Which doctor, which test?
- Incidental leukocytes without symptoms: Family physician. If needed, it is rechecked with a clean sample. If you are not pregnant, culture and antibiotics are generally not needed.
- Burning, frequent urination, urgency: Family physician. With typical complaints, the treatment decision is often based on the history. A culture is ordered if the complaints are not typical, if there is no response to treatment, or if they recur within 4 weeks.
- Pregnancy: Obstetrics and gynecology. A urine culture is ordered.
- Men: Family physician or urology. UKHSA recommends sending a culture before antibiotics when infection is suspected in a man. Depending on the sexual history, chlamydia and gonorrhea tests are added.
- Recurrent or culture-negative leukocytes: Urology or infectious diseases. Urine culture for tuberculosis, tests for sexually transmitted infections, and imaging may be considered.
- Planned urological procedure: Urology. A culture is taken before the procedure and treatment is given according to the result.
In Türkiye
- National microbiology guideline: According to the 2020 guideline of the Turkish Society of Clinical Microbiology Specialists (KLİMUD), pyuria alone is not sufficient to diagnose a urinary tract infection. For diagnosis, symptoms, the inflammatory response and bacteria in culture are evaluated together.
- A common finding in older adults: KLİMUD notes that asymptomatic bacteriuria may be present in 10% of men and 20% of women over 80.
- Notifiable agents: Chlamydia trachomatis and the tuberculosis bacillus, which come to mind with sterile pyuria, are among the notifiable disease agents in Türkiye.
- Sampling standard: The Ministry's 2024 Total Testing Process Guideline recommends first-void urine (the first 10 mL) for urethritis and midstream urine for the bladder. Your physician should specify which sample they want.
- e-Nabız: You can see your past urine tests on the same screen. Recurrent findings are more meaningful than a single result.
When should you seek emergency care?
- If there is fever, chills, lower back or flank pain and vomiting, go to the emergency department the same day. This picture may be a kidney infection.
- If there is confusion, marked weakness or low blood pressure, call 112 (the emergency number in Türkiye).
- During pregnancy, if there is fever, flank pain or regular contractions, go to the obstetric emergency department without delay.
- If you cannot pass urine at all or there is bloody urine with clots, go to the emergency department.
- If an older relative has new-onset confusion together with fever, emergency assessment is needed.
- If the laboratory has called you about a critical value, do what you are told without delay.
Related tests
- Lab Test Guide: all tests
- How to read urinalysis results
- What does growth in a urine culture mean?
- Protein in the urine (proteinuria)
- Urinary tract infection guide
- Urinary tract infection after sex
- Tests for sexually transmitted infections
What changed? (October 2026)
- New page. Consistent with the EAU Guidelines on Urological Infections 2026 (limited update March 2026) and the IDSA 2019 asymptomatic bacteriuria guideline.
- Definitions of pyuria were taken from the KLİMUD 2020 guideline, and primary care interpretation rules from UKHSA's July 2025 update.
Sources
- Klinik Mikrobiyoloji Uzmanlık Derneği (KLİMUD). Üriner Sistem Örneklerinin Laboratuvar Tanısı Rehberi. 2nd edition, Ver 2.1, 2020. https://www.klimud.org/uploads/content/%C3%9Criner%20Sistem%20%C3%96rneklerinin%20Laboratuvar%20Tan%C4%B1s%C4%B1%20(Ver2.1-2020).pdf (accessed October 2, 2026)
- Nicolle LE, Gupta K, Bradley SF et al. Clinical Practice Guideline for the Management of Asymptomatic Bacteriuria: 2019 Update by the Infectious Diseases Society of America. Clin Infect Dis 2019;68(10):e83-e110. https://doi.org/10.1093/cid/ciy1121 (accessed October 2, 2026)
- European Association of Urology. EAU Guidelines on Urological Infections. 2026 (limited update March 2026). https://uroweb.org/guidelines/urological-infections (accessed October 2, 2026)
- UK Health Security Agency, NHS England. Diagnosis of urinary tract infections: quick reference tools for primary care. Updated July 7, 2025. https://www.gov.uk/government/publications/urinary-tract-infection-diagnosis/diagnosis-of-urinary-tract-infections-quick-reference-tools-for-primary-care (accessed October 2, 2026)
- T.C. Sağlık Bakanlığı Sağlık Hizmetleri Genel Müdürlüğü. Tıbbi Biyokimya Toplam Test Süreci Rehberi. May 2024, Yayın No 1287. https://dosyamerkez.saglik.gov.tr/Eklenti/48692/0/tibbi-biyokimya-toplam-test-sureci-rehberipdf.pdf (accessed October 2, 2026)
- T.C. Sağlık Bakanlığı Sağlık Hizmetleri Genel Müdürlüğü. Karar Sınırı (Eşik Değer), Kritik Değer (Panik Değer) ve Ölçüm Birimlerinin Harmonizasyonu Prosedürü. 22.09.2020. https://dosyamerkez.saglik.gov.tr/Eklenti/15143/0/karar-siniri-esik-deger-kriek42009846pdf.pdf (accessed October 2, 2026)
- T.C. Sağlık Bakanlığı. e-Nabız Kullanım Kılavuzu V2.1. 31.05.2025. https://enabiz.gov.tr/document/User_Manual.pdf (accessed October 2, 2026)
Frequently asked questions
My urine leukocytes came back 3+. Should I take antibiotics?
If you have no complaints and are not pregnant, it is usually not needed. If you have burning, frequent urination or fever, see a physician. Do not start leftover antibiotics at home on your own; this can affect the culture result.
What does it mean if leukocytes in the urine show up in red on e-Nabız (Türkiye's national health record app)?
The red color shows that the value is outside the laboratory's reference range. It is not by itself a diagnosis of infection. Show the result to your family physician together with your complaints.
What does it mean if nitrite is negative and leukocytes are positive?
It may be an infection, or it may be another cause. For nitrite to turn positive, urine needs to stay in the bladder for a few hours. Some bacteria also do not produce nitrite. If you have complaints, your physician may order a culture.
What happens if leukocytes are found in the urine during pregnancy?
A urine culture is important in pregnancy. IDSA and EAU recommend screening for and treating even asymptomatic bacteriuria in pregnancy. Your doctor chooses a medication that is safe in pregnancy according to the culture result.
There are leukocytes in my urine but no growth in the culture. Why?
This is called sterile pyuria. Recent antibiotic use, chlamydia, kidney stones and, rarely, tuberculosis can be the cause. If the condition persists, an evaluation by urology or infectious diseases is needed.
Why are leukocytes in the urine common in older adults?
Asymptomatic bacteriuria increases with age. According to UKHSA, by age 80 about half of older adults living in care homes may have bacteria in their urine without an infection. For this reason, if there is no fever or urinary complaint, treatment is generally not needed.
