How to interpret a urinalysis (urine analysis) result?

From the Guidelines

To interpret a urinalysis result, start by examining the physical properties of the urine sample, then review the chemical analysis, and finally assess the microscopic examination results, considering the patient's clinical presentation and other diagnostic tests, as recommended by the American College of Physicians 1. When evaluating urinalysis results, it's essential to consider the potential for false positives or false negatives due to various factors such as contamination, exercise, or urinary tract infection, as outlined in the study by the American Journal of Kidney Diseases 1. The following steps can be taken to interpret urinalysis results:

• Examine the physical properties of the urine sample, including color, clarity, and specific gravity, which can indicate hydration status and kidney concentrating ability.
• Review the chemical analysis, looking for the presence of abnormal substances such as protein, glucose, ketones, blood, leukocyte esterase, and nitrites, which can suggest various pathological conditions.
• Assess the microscopic examination results, including the presence and quantity of red blood cells, white blood cells, epithelial cells, bacteria, and casts, which can indicate various pathological conditions. Some key points to consider when interpreting urinalysis results include:
• The presence of protein in the urine can suggest kidney problems, while glucose in the urine can indicate diabetes.
• Blood in the urine (hematuria) can signal various conditions from infection to cancer, and leukocyte esterase and nitrites can suggest urinary tract infection if positive.
• The microscopic examination can reveal cellular elements that are minimal or absent in normal urine, and their presence and quantity can indicate various pathological conditions. It's also important to consider the patient's clinical presentation and other diagnostic tests when interpreting urinalysis results, as abnormal findings often require follow-up testing or clinical correlation for accurate diagnosis and treatment planning, as recommended by the American College of Physicians 1. In cases of hematuria, it is recommended to confirm heme-positive results of dipstick testing with microscopic urinalysis that demonstrates 3 or more erythrocytes per high-powered field before initiating further evaluation, as suggested by the study published in the Annals of Internal Medicine 1. Additionally, urology referral for cystoscopy and imaging should be considered in adults with microscopically confirmed hematuria in the absence of some demonstrable benign cause, as recommended by the American College of Physicians 1.

From the Research

Interpreting Urinalysis Results

To interpret a urinalysis result, it is essential to evaluate the physical characteristics, biochemical parameters, and microscopic sediment evaluation of the urine sample 2. The physical characteristics include color, clarity, and volume, while biochemical parameters include urine pH, blood, glucose, ketones, bilirubin, urobilinogen, and protein. Microscopic sediment evaluation includes the presence of red blood cells (RBC), white blood cells (WBC), organisms, epithelial cells, crystals, and casts.

Factors Influencing Urinalysis Results

Several factors can influence the accuracy of urinalysis results, including:

• Collection method: The method of collecting the urine sample can affect the results, and it is essential to interpret the results accordingly 2.
• Diet and hydration status: Diet, hydration status, and medications can alter urine color, odor, clarity, specific gravity, and pH 3.
• Exercise and physical activity: Intensive physical exercise can also affect urine characteristics 3.

Components of Urinalysis

A complete urinalysis includes:

• Physical examination: Description of color, odor, clarity, volume, and specific gravity of the urine 4, 5.
• Chemical examination: Identification of protein, blood cells, glucose, pH, bilirubin, urobilinogen, ketone bodies, nitrites, and leukocyte esterase in the urine 4, 5.
• Microscopic examination: Detection of crystals, cells, casts, and microorganisms in the urine sediment 4, 5.

Common Abnormalities and Their Causes

Some common abnormalities found in urinalysis results and their possible causes include:

• Cloudy urine: Precipitated phosphate crystals in alkaline urine or pyuria 5.
• Strong odor: Concentrated specimen or urinary tract infection 5.
• Microhematuria: Benign or life-threatening causes, including glomerular, renal, and urologic causes 5.
• Proteinuria: Transient or persistent, requiring further work-up if persistent 5.