Diagnosis of Urinary Tract Stones

The diagnosis of urinary tract stones aims to confirm whether a stone is present, determine its location and size, and assess whether it is causing urinary tract obstruction. These findings are important for evaluating the severity of the condition and determining the most appropriate treatment for each patient.

Doctors consider the patient’s symptoms, medical history, physical examination, and additional diagnostic tests as appropriate. Tests that may be used to diagnose urinary tract stones include CT scans, urinalysis, blood tests, ultrasound, and plain X-rays (KUB X-ray).

What Tests Are Used to Diagnose Urinary Tract Stones?

1. Computed Tomography (CT Scan)

Non-contrast CT KUB (Kidneys, Ureters, and Bladder) is a highly accurate imaging test for detecting urinary tract stones and is commonly used as a standard imaging method in patients with acute stone-related pain.

A CT scan can help determine:

• Whether a urinary tract stone is present
• The location of the stone
• The size of the stone
• Whether the stone is causing urinary tract obstruction
• Whether hydronephrosis is present as a result of obstruction
• Whether another abnormality may be responsible for the patient’s pain

CT can also assess the density of a stone using Hounsfield Units (HU). This information may help doctors evaluate the characteristics of the stone and may be considered when planning treatment in some patients.

Because CT involves radiation exposure, doctors will consider the necessity of the examination and select the most appropriate imaging method for each patient.

2. Urinalysis

Urinalysis is a basic and important test for patients suspected of having urinary tract stones. It can help detect abnormalities associated with stones, including:

• Red blood cells or blood in the urine
• Signs of urinary tract infection
• Urine acidity or alkalinity (pH)
• Certain types of mineral crystals

Many patients with urinary tract stones may have blood in the urine. However, a normal urinalysis does not rule out the possibility of a urinary tract stone. Doctors therefore interpret the results together with symptoms and other diagnostic findings.

3. Blood Tests

Blood tests help assess overall health, kidney function, and complications that may be associated with urinary tract stones. Depending on the patient’s condition, doctors may assess:

• Kidney function
• Signs of infection
• Blood calcium levels
• Uric acid levels

For patients with fever and suspected urinary tract stones, blood tests can help assess infection and its severity and provide additional information for treatment planning.

4. Ultrasound

Ultrasound does not use radiation and is convenient and safe for certain patient groups. It may be particularly useful for:

• Pregnant women
• Children
• Patients requiring periodic stone follow-up
• Assessing hydronephrosis caused by urinary tract obstruction

However, ultrasound has limitations in detecting stones in certain locations, particularly stones in the ureter and small stones. Therefore, a negative ultrasound does not always confirm that a stone is absent or has passed.

If it is necessary to confirm the location of a stone or determine whether it remains present, a CT scan may be considered depending on the patient’s condition.

5. Plain X-ray (KUB X-ray)

A KUB X-ray is an X-ray examination of the kidneys, ureters, and bladder. It can detect some stones that are radiopaque, but not all urinary tract stones can be seen on a plain X-ray.

Because of these limitations, KUB X-ray is less sensitive than CT for detecting urinary tract stones. It is often used to follow up certain types of stones after diagnosis or treatment rather than as the primary test for the initial diagnosis.

Do All Patients Need Every Test?

No.

Not every patient needs every diagnostic test. Doctors select examinations based on each patient’s symptoms and individual circumstances, including:

• The type and severity of symptoms
• Age
• Underlying medical conditions
• Previous history of kidney or urinary stones
• The possibility of infection
• The risk of urinary tract obstruction
• The need for treatment planning
• Patient safety

Some patients may initially undergo urinalysis and ultrasound, while patients with severe pain or suspected urinary tract obstruction may require an additional CT scan to obtain more detailed and accurate information.

Summary: Diagnosis of Urinary Tract Stones

Diagnosing urinary tract stones does not rely on a single test. Doctors combine the patient’s symptoms, medical history, physical examination, and appropriate diagnostic tests to reach a diagnosis and determine the most suitable treatment approach.

Non-contrast CT KUB is a highly accurate imaging method that plays an important role in detecting urinary tract stones and assessing their location, size, and associated urinary tract obstruction. Urinalysis, blood tests, and ultrasound also play important roles in evaluating associated conditions and supporting treatment planning.

Once the location and size of a stone are known, one of the most common questions is: “Can the stone pass on its own?” The answer depends on several factors, including the stone’s size and location.