Blood in Urine With Back or Side Pain: When to Seek Emergency Care

Blood in your urine together with pain in your back or side should be checked by a clinician soon, and some combinations need emergency care the same day: fever or chills, vomiting, pain you cannot control, or peeing very little.

The most common cause of this pairing is a kidney stone, but infection and other kidney or bladder problems can look the same from the outside. You cannot tell which one it is at home, so this guide focuses on what makes it urgent and what the evaluation involves.

What blood in the urine looks like

Blood can turn urine pink, red, brown or the color of cola. Sometimes there are small clots. A small amount may only show up on a urine test. Some foods, such as beets, and some medicines can change urine color without blood being present, which is one reason a urine test matters.

The pain that comes with it matters too. Pain from the kidney or ureter is usually felt in the side or back, below the ribs, and can spread to the lower belly or groin. It may come in waves.

Possible causes

These are possibilities, not a diagnosis. Several can occur together.

• Kidney or ureter stone. Often sudden, severe, wave-like flank pain with nausea and blood in the urine. See our page on kidney stone emergency care.
• Kidney infection. Fever, chills, flank pain and burning when you pee point toward infection. Read more about kidney infection care.
• Bladder infection. Burning, urgency and blood, usually with lower belly discomfort rather than back pain.
• Injury. A hit to the back or side, a fall or a crash can bruise a kidney.
• Other causes. Kidney disease, an enlarged prostate, blood thinners, intense exercise and, less often, tumors of the kidney or bladder. These need follow-up even when pain settles.

Warning signs that need emergency care today

• Fever, shaking chills or feeling very unwell
• Vomiting that stops you keeping fluids or medicine down
• Pain that over-the-counter or prescribed medicine does not control
• Passing very little urine, or none at all
• Large clots, or trouble passing urine because of clots
• Pregnancy, a single kidney, a kidney transplant or known kidney disease
• Blood thinners with heavy bleeding
• Recent injury to the back, side or belly

A stone that blocks the kidney while urine is infected can become serious quickly, which is why fever plus flank pain is treated as urgent.

What the ER will check

The emergency team will ask when the pain started, where it is, whether it comes in waves, and about fever, past stones, medicines and recent injuries. Then:

• Vital signs, including temperature and blood pressure
• A urine test for blood and signs of infection, often with a culture
• Blood tests to check kidney function and infection
• Imaging when needed, such as a CT scan or ultrasound, to look for a stone or blockage
• Pain and nausea relief, often started early

Eastex ER lists on-site lab testing and imaging. If you need a hospital procedure, such as draining a blocked and infected kidney, the team arranges transfer. Eastex ER is a freestanding emergency room without inpatient beds or a urology operating room.

When your doctor is the right next step

If you notice blood in your urine but have no pain, no fever and feel well, it is usually not an emergency, but it still needs a prompt visit with your doctor. Painless visible blood in the urine in adults can be a sign of a bladder or kidney problem that needs testing, even if it stops. Do not ignore it because it went away.

What to tell the doctor

• When you first saw blood, and whether it was pink, red or brown
• Where the pain is and whether it spreads or comes in waves
• Any fever, chills, nausea or vomiting
• Past kidney stones or urinary infections
• Blood thinners, aspirin or other medicines
• Recent heavy exercise or any injury

Use our what to bring checklist if you have time.