What does the presence of leukocyte esterase and red blood cells in my urinalysis indicate?

Urinalysis Findings of Leukocyte Esterase and RBCs Indicate Possible Urinary Tract Infection

Your urinalysis findings of leukocyte esterase small (25 ml/dg) and RBC 3-10/HPF strongly suggest inflammation in your urinary tract, most likely indicating a urinary tract infection that requires further evaluation and possible treatment.

Understanding Your Urinalysis Results

• Leukocyte esterase is an enzyme released by white blood cells (leukocytes) and indicates the presence of pyuria (white blood cells in urine), which is a sign of inflammation in the urinary tract 1
• The presence of leukocyte esterase has moderate sensitivity (83%) but limited specificity (78%) for detecting urinary tract infections 1
• Red blood cells (RBC) at 3-10/HPF meets the clinical definition of microscopic hematuria, which is defined as three or more red blood cells per high-power field 2
• The combination of both leukocyte esterase and microscopic hematuria increases the likelihood of a significant underlying condition 1

Clinical Significance

• When leukocyte esterase is positive AND you have symptoms like dysuria (painful urination), frequency, urgency, fever, or gross hematuria, this strongly suggests a urinary tract infection 1
• The Infectious Diseases Society of America recommends that if pyuria (≥10 WBCs/high-power field or positive leukocyte esterase) is present, a urine culture should be obtained to confirm infection 2
• Patients with pyuria are significantly more likely to have a positive urine culture (36.4%) compared to those without pyuria (3.3%) 3
• The degree of leukocyte esterase correlates with the risk of positive culture - higher levels indicate greater likelihood of infection 3

Next Steps

• If you are experiencing symptoms such as dysuria, frequency, urgency, fever, or gross hematuria, you should seek medical evaluation for a possible urinary tract infection 1
• Your healthcare provider should obtain a urine culture before starting antibiotics to confirm the infection and determine the appropriate treatment 2, 1
• Adding a nitrite test can improve diagnostic accuracy, as the combination of leukocyte esterase and nitrite testing increases sensitivity to 93% and specificity to 96% 4, 1
• If you have no symptoms, these findings may still warrant evaluation, especially if you have risk factors for significant disease 2

Risk Factors Requiring Further Evaluation

• Age over 40 years 2
• Smoking history 2
• History of gross hematuria 2
• History of urologic disorders or diseases 2
• History of urinary tract infections 2
• Occupational exposure to chemicals or dyes 2
• History of irritative voiding symptoms 2

Common Pitfalls to Avoid

• Do not ignore these findings, even if you are asymptomatic, as they may indicate significant underlying conditions 2
• Avoid self-diagnosis based solely on dipstick results, as leukocyte esterase has limited specificity and should be confirmed by microscopic evaluation 2
• In the absence of symptoms, avoid unnecessary antibiotic treatment based solely on these laboratory findings, as asymptomatic bacteriuria with pyuria is common, especially in older adults 1
• Remember that certain conditions like kidney stones can also cause both hematuria and pyuria - 14.2% of patients with renal colic have associated pyuria 3

If you are experiencing symptoms, these findings strongly suggest a urinary tract infection requiring medical attention. If you are asymptomatic, these findings still warrant discussion with your healthcare provider to determine if further evaluation is necessary.