Kidney stone

3 things to know first

1. Some stones cause no symptoms. A stone found by chance is different from one blocking urine flow.
2. Location matters. The report may say the stone is in the kidney or has moved into a ureter.
3. Fever with blockage is urgent. Infection behind an obstruction needs prompt medical care.

What it is

A kidney stone, also called a renal calculus, is a hard deposit formed from substances in urine. Stones can remain in a kidney or move through a ureter, the tube that carries urine to the bladder. A stone's size, position, and whether it blocks drainage influence symptoms and the next step.

Why it appears on your report

CT without contrast is commonly used to show a stone's size and location and whether it is associated with obstruction. Ultrasound can show stones and widening of the kidney's collecting system, although some small stones are difficult to see. Not every stone appears on a plain abdominal X-ray. Reports may also mention hydronephrosis when urine backs up.

How serious is it

Many small, non-obstructing stones are managed without an urgent procedure. A stone causing severe pain, reduced urine flow, infection, or kidney problems requires closer evaluation. The report alone cannot tell whether a stone will pass or whether it is the only cause of pain.

When to seek care urgently

Seek urgent care for fever or chills with flank pain, inability to pass urine, pain with repeated vomiting, or severe symptoms in someone with one functioning kidney.

What usually happens next

1. Review symptoms, urine and blood tests, and kidney function.
2. Confirm the stone's size and exact position and whether drainage is blocked.
3. Discuss observation, symptom management, or urology review with the clinician.

A simple analogy

Think of the urinary tract as a drainage pipe. A small pebble may rest in a wider section; when it reaches a narrower section, flow and comfort can change.

Further reading

• NIDDK — Diagnosis of Kidney Stones
• NIDDK — Urinary Tract Imaging