Urine Examination
Did you know?
A Routine Urine Examination (RUE) is a simple yet powerful test performed on a urine sample to evaluate kidney function and help diagnose various medical conditions.
What should you look for in a normal urine report?
A routine urine report provides information about the physical, chemical, and microscopic properties of urine. Understanding these can help avoid unnecessary, expensive, or invasive tests.
When should this test be done?
While this test is useful for general health assessment, it is especially recommended if you have:
- Frequent urination
- Pain or burning while urinating
- Fever
- Backache
- Fatigue
- Symptoms suggestive of infection or kidney problems
What is checked in a Routine Urine Examination?
The test includes three major components:
1. Physical Examination
- Colour
- Quantity
- Appearance (clarity/turbidity)
2. Chemical Examination
Checks for:
- Proteins
- Glucose
- Bilirubin
- Ketones
- Blood
- pH and specific gravity (hydration)
3. Microscopic Examination
Looks for:
- Bacteria
- Pus cells (WBCs)
- Red blood cells
- Crystals
- Casts
- Epithelial cells
What problems can a urine examination detect?
A routine urine test can reveal:
- Infections (bacteria, pus cells)
- Kidney dysfunction (presence of proteins, casts, crystals)
- Liver disorders (bilirubin in urine)
- Diabetes (glucose, ketones)
- Dehydration
- Kidney stones
- Metabolic disorders
What is a clean-catch urine sample?
A clean-catch sample reduces contamination and ensures accurate results.
Follow these steps:
- Wash and clean the perineal area properly.
- Begin urinating into the toilet.
- Stop midstream.
- Place the sterile container near you.
- Pass the rest of the urine into the container without touching its inside walls.
- Close the lid tightly and submit the sample.
What is a physical examination of urine?
The physical examination assesses:
- Colour
- Volume
- Appearance (clarity)
What is the normal appearance of urine?
Normal urine is:
- Clear
- Yellow
- Without turbidity or foam
When does urine appear cloudy?
Urine may appear cloudy or turbid when:
- Certain urinary infections damage the bladder lining
- Pus cells, bacteria, or mucus are present
- Crystals form due to dehydration
When does urine appear red?
Urine may appear red due to the presence of blood (hematuria). Common causes include:
- Urinary Tract Infection (UTI)
- Kidney or urinary tract stones
- Certain medications such as aspirin and cyclophosphamide
- Strenuous exercise (e.g., long-distance running)
- Benign Prostatic Hyperplasia (BPH)
- Cancers of the urinary bladder, prostate, or kidney
Can a urine test detect the source of bleeding?
Yes. By examining red blood cells under the microscope, we can often determine whether the blood is coming from the kidneys or the lower urinary tract (bladder/urethra).
Can urine appear red without blood?
Yes. Urine can turn red due to:
- Food colouring
- Laxatives
- Berries
- Certain medicines, including multivitamins and anti-tuberculosis drugs
Why does urine appear frothy?
Frothy or foamy urine occurs when proteins are lost in the urine (proteinuria).
What is a microscopic urine examination?
It is an examination of urine under a microscope to look for:
- Bacteria
- Red blood cells
- White blood cells
- Pus cells
- Crystals
When does urine smell strange?
The smell of urine can change due to:
- Foods rich in vitamin B6 (e.g., bananas, salmon), especially with low water intake
- Foods like garlic, ginger, and coffee
- UTIs caused by urea-splitting organisms (produce a strong ammonia smell)
- Uncontrolled diabetes
- Liver disease
What are signs of a UTI in a routine urine analysis report?
- Presence of pus cells (WBCs)
- Positive leukocyte esterase (an enzyme released by WBCs fighting infection)
What is a urine dipstick test?
A urine dipstick is a strip that, when dipped into a urine sample, can detect:
- Urine acidity (pH)
- Glucose
- Protein
- Blood
- Bilirubin
What does the presence of protein in urine mean?
The kidneys normally filter blood and prevent protein loss.
Protein in urine (proteinuria) indicates a problem with kidney filtration.
Conditions where small amounts of protein may appear (0–14 mg/dL or <80 mg/day):
- Infections
- Excessive exercise
- High blood pressure
- Pregnancy
Detecting this early helps diagnose and treat disease before complications occur.
When is proteinuria dangerous?
Protein loss >150 mg/day may indicate:
- Nephrotic syndrome
- Chronic kidney disease
- End-stage renal disease
- Acute or chronic renal failure
What does glucose in urine mean?
Normally, urine contains no glucose (0–0.8 mmol/L).
Elevated glucose levels suggest:
- Kidney disease
- Endocrine disorders like diabetes
Which medicines can cause glucose in urine (glycosuria)?
Some anti-diabetic medications—such as metformin and other glucose-lowering drugs—may increase glucose excretion in urine.
What are casts in urine, and why do they matter?
Casts are tube-shaped particles seen on microscopic examination. They may be made of:
- Red blood cells
- White blood cells
- Kidney tubular cells
- Fat cells
They help diagnose:
- Kidney infections
- Glomerular diseases
- Interstitial kidney diseases
Here is a sample of a urine test report showing reference ranges:
What is the significance of ketones in urine?
Normally, the body uses glucose as its primary energy source.
However, in conditions such as:
- Diabetes mellitus
- Inadequate food intake
- Starvation or prolonged fasting
…the body begins to use fat for energy. As fats break down, ketones are produced and eliminated in urine.
Small amounts of ketones are not harmful, but in people with diabetes, the presence of ketones is a warning sign of a potentially life-threatening condition called Diabetic Ketoacidosis (DKA).
Can crystals be normally found in urine?
Yes. Small amounts of crystals can be seen in a normal urine sample.
However, dehydration and excessive protein intake can increase crystal formation (crystalluria).
What are the different types of crystals in urine?
Various types of crystals may appear in urine. In small numbers they are harmless, but in larger quantities they may suggest underlying issues:
- Calcium oxalate crystals – associated with high vitamin D levels or kidney stones
- Uric acid crystals – seen in gout or high uric acid levels
- Triple phosphate (struvite) crystals – indicate alkaline urine and may suggest infection or predisposition to kidney stones
- Cystine crystals – seen in the genetic disorder cystinuria
Why is there mucus in urine and how is it treated?
Mucus in urine may appear in:
- Urinary tract infections
- Sexually transmitted infections (STIs)
- Dehydration
- Kidney stones
Treatment depends on the underlying cause. Hydration, treating infections, and addressing stones usually resolve it.
(Classically, medications like propantheline were used for bladder irritation, but they are not routinely recommended today unless prescribed by a clinician.)
Remember
A simple routine urinalysis is a valuable screening tool. It can provide important information about your:
- Overall health
- Kidney function
- Metabolic disorders
- Ongoing infections
- Risk of future diseases
Dr. Ayesha Azam Khan