Protein or blood in the urine
Protein or blood in the urine is not always a serious illness, but sometimes it is the first sign of damage to the kidney's filters (the glomeruli). This page explains what these findings mean, which tests settle the question, what nephrotic syndrome is and when to act quickly.
What do protein and blood in the urine mean?
The kidneys have tiny filters called glomeruli that clean the blood. NIDDK writes that when these filters are damaged, protein and sometimes red blood cells leak through them into the urine. These are the two key findings:
- Proteinuria (protein or albumin in the urine). NKF explains that albumin is a protein that a healthy kidney keeps almost entirely in the blood. Protein in the urine is not a separate disease. It is a sign of kidney damage and can be seen even when eGFR is still above 60.
- Hematuria (blood in the urine). Sometimes the urine turns pink or cola-coloured, but NIDDK points out that blood is often seen only under a microscope. The blood may come from the kidney or from the bladder, ureter or prostate (NHS).
Symptoms
Many patients have no symptoms. Possible symptoms (NIDDK and NKF):
- Foamy urine.
- Swollen feet and ankles, or swelling around the eyes, especially in the morning.
- Weight gain from holding on to water, and new or higher blood pressure.
- Pink or brown urine.
When a lot of protein is lost, a group of findings called nephrotic syndrome develops. NIDDK describes it as heavy loss of protein, low blood albumin, swelling and high blood fats. NKF writes that it is not a separate disease and can occur in any condition that damages the filters, whether it affects only the kidney or is a whole-body illness such as diabetes or lupus.
Who should be seen?
- Someone whose urine test showed protein or blood, especially if the test was repeated and is still positive.
- Someone with persistent foamy urine or new swelling of the feet or around the eyes.
- Someone with diabetes, high blood pressure, lupus or a family history of kidney disease.
- Anyone whose urine has turned pink, red or brown. NHS says any suspected blood in the urine, even a small amount, should be checked. Beetroot and some medicines can also change urine colour, but do not decide this yourself.
How is it assessed?
NIDDK and NKF describe assessment like this:
- A urine test for protein and red blood cells. The more precise test is the urine albumin-to-creatinine ratio (ACR). NKF says less than 30 mg/g is normal and 30 or more counts as albuminuria. The result usually needs to be repeated within a few months to see whether it persists.
- A blood test for creatinine and eGFR, which show kidney function, and for blood albumin.
- An ultrasound or CT scan to see the size and shape of the kidneys.
- A kidney biopsy if needed. NIDDK says a biopsy can confirm glomerular disease and identify the cause.
- Checks for other conditions that can be the cause, such as diabetes, lupus and infections such as hepatitis.
If there is blood in the urine, NHS says the doctor decides based on history, examination and tests, and may refer you to a specialist for further tests. NHS stresses that the cause of blood may be cancer too and early discovery makes treatment easier, so do not delay.
What does treatment look like overall?
NIDDK says treatment depends on the cause and how much damage there is. Some diseases improve when the cause is treated, some come back and some progress to kidney failure. The groups of medicines NIDDK names are:
- Medicines that lower blood pressure and urine protein and slow the fall in kidney function.
- Water tablets (diuretics) to reduce swelling.
- Medicines that lower blood fats.
- Medicines that suppress the immune system in inflammatory diseases of the filters.
- A group of diabetes medicines that may also slow the progress of kidney disease.
The type of medicine, dose and duration are set only by the doctor, and medicines that suppress the immune system need close monitoring. NKF says that in nephrotic syndrome a high-protein diet does not help and may make things worse. Cutting down on salt can help with blood pressure and swelling. The right amount of protein and salt differs for each patient.
What you can do
- Have urine and blood tests at the times your doctor has said and keep the results.
- Measure blood pressure at home and write it down.
- Keep an eye on weight and swelling. NKF says to tell your doctor if swelling gets worse or becomes painful.
- Do not stop medicines without your doctor’s advice. Do not take anti-inflammatory painkillers without asking.
- Set your salt and protein with your doctor or dietitian and do not make up numbers yourself.
- If you have diabetes, take blood sugar control seriously.
When to get urgent help
- Your urine has become very scant or stopped, or swelling and weight have suddenly increased.
- You have shortness of breath or chest pain.
- You have seen a lot of blood or clots in the urine, or you cannot pass urine.
- You have fever and chills or severe flank pain together with blood in the urine.
- You have developed severe nausea and vomiting or confusion.
In Iran, call 115, Iran’s emergency number. For blood in the urine without these signs, NHS says to make an urgent appointment with a doctor. See the full list in the guide “When to get urgent help”.
Frequently asked questions
My urine is foamy. Does that mean I have protein in it?
Possibly, but not always. NKF and NIDDK say a lot of persistent foam can be a sign of protein in the urine, and foam once or twice does not necessarily have anything to do with the kidneys. Only a urine test settles it. See also the article "When does foamy urine matter?"
Protein was seen in my urine once. Should I worry?
NKF writes that protein in the urine may be temporary, for example with dehydration, hard exercise, fever or infection. For this reason the doctor usually repeats the test and counts it as a sign of kidney damage only when the result persists. There is no need for unnecessary worry, but follow-up is essential.
Does blood in the urine mean kidney stones?
NHS says blood in the urine has different causes: a urinary infection, a stone, an enlarged prostate, disease of the kidney's filters and sometimes cancer. For this reason even a small amount should be checked. The cause cannot be guessed without a check.
Is a kidney biopsy always needed to find the cause?
Not always. NIDDK says assessment starts with urine and blood tests and sometimes imaging is needed. A kidney biopsy identifies the cause in some glomerular diseases, and the decision about it is for the nephrologist.
Is swelling around the eyes or legs always from the kidneys?
No. NKF says swelling can also come from a heart or liver problem. But new swelling, especially with foamy urine, is a good reason to have a urine test and see a doctor.