A little foam when you pee is common and is usually caused by a strong stream, concentrated morning urine or toilet cleaner in the bowl. If your urine foams a lot every time for several days, especially if you have swelling, diabetes or high blood pressure, it may be protein. A urine test at your GP gives the answer.
By the Nyrami editorial teamPublished 2 October 20266 min read
Many people get worried when they see foam in the toilet, often after reading that it can be a sign of kidney disease. Usually the explanation is completely harmless. But foam that comes back every time can be protein in the urine, and that is easy to check. Here is how to tell the two apart, and what your doctor will do.
Foamy urine most often just means that air has got into the urine, because the stream hit the water with force or the urine was concentrated. Bubbles like these disappear quickly. Foam that stays, is dense and white, or appears every time you pee for several days, can however mean that the urine contains protein, also called albumin.
Healthy kidneys keep proteins in the blood. When the filters in the kidneys are damaged, protein leaks into the urine, and protein makes bubbles last, in the same way that egg white turns into foam when you whisk it. But foam is an unreliable sign. Of 72 patients who came to a hospital in South Korea because their urine was foamy, around one in five had clear protein in the urine. Most did not, but enough did to make a urine test worthwhile.
Morning urine is often more concentrated because you have not had anything to drink for many hours, and your bladder is full, so the stream is strong. Both give more foam. This is common and harmless, especially if the foam goes away once you have had something to drink during the day. Other common and harmless causes are:
Foamy urine is rarely dangerous in itself, but persistent foam can be the first visible sign that the kidneys are leaking protein. It is worth checking if the foam appears every time for more than a few days, does not go away when you drink more, or gets worse over time. This applies especially if you also have any of the following:
Protein in the urine usually causes no symptoms. That is why the urine test, not the foam, gives the answer. Read more about what the finding means in the guide to protein in urine.
Yes. Diabetes and high blood pressure are the most common reasons the kidneys start leaking protein, because over time they damage the small blood vessels in the kidneys. Even so, foam appears late, and many people who leak protein never see any foam. If you have diabetes, the Norwegian Directorate of Health (Helsedirektoratet) recommends measuring albumin in your urine every year, whether you see foam or not.
Other causes of protein in the urine are inflammation of the kidney filters (glomerulonephritis), such as IgA nephropathy, inherited kidney diseases and autoimmune diseases such as lupus. Read more about diabetes and the kidneys and blood pressure and the kidneys.
Nephrotic syndrome means that the kidneys leak a very large amount of protein, more than 3 grams a day. This leaves too little protein in the blood, and the body holds on to water. Typical signs are very foamy urine and swelling around the eyes, in the face, feet and lower legs, often with tiredness and poor appetite. In children it is most often caused by inflammation of the kidney filters, in adults also by diabetes and other diseases. The condition is rare and should always be investigated by a doctor.
A little foam is just as common when you are pregnant as at other times. But protein in the urine together with new high blood pressure after week 20 can be a sign of pre-eclampsia, which affects around three per cent of pregnancies. That is why your midwife or doctor measures your blood pressure and checks your urine at antenatal check-ups.
Protein in the urine alone is not enough for the diagnosis, and foam cannot tell protein from air. If you are wondering, mention it at your next check-up. If you get a severe or persistent headache, visual disturbances such as flickering, pain at the top of your stomach, nausea or sudden swelling in your face, hands or feet, contact your doctor, midwife or maternity ward quickly, whatever your urine looks like.
Your doctor checks for protein with a urine test. Often a dipstick is dipped in the sample first, which gives a rough answer with plus signs. The most reliable test is the urine albumin to creatinine ratio (u-AKR in Norway, often called ACR or UACR elsewhere), which measures albumin relative to creatinine in the same sample. That way it does not matter whether the urine is concentrated or dilute. Your doctor will often also take a blood test showing eGFR, how well the kidneys filter, and measure your blood pressure.
| Ratio (mg/mmol) | What it means |
|---|---|
| Below 3 mg/mmol | Normal |
| 3 to 29 mg/mmol | Moderately increased |
| 30 to 299 mg/mmol | Severely increased |
| 300 mg/mmol or more | Nephrotic range |
Bring your first morning urine, and avoid hard exercise in the three days before the test. If you have a fever, a urinary tract infection or your period, you should wait. One raised result is not enough: Helsedirektoratet recommends a new test within three months, and only when two out of three are raised is it considered persistent. Read more about how kidney disease is detected.
Book an appointment with your GP (fastlege) if your urine foams every time for more than a few days, or if you have diabetes, high blood pressure or kidney disease in the family and have not had a urine albumin test in the past year. Bring a morning urine sample so the test can be done the same day.
Contact a doctor the same day, or the out-of-hours service (legevakt) on 116 117, if you swell up a lot in your face, around your eyes or in your legs, pass much less urine than usual or have blood in your urine. If you are pregnant and have a severe headache, visual disturbances or pain at the top of your stomach, call your doctor, midwife or maternity ward straight away. If life is at risk, call 113.
Once you have your urine test result, you can enter your albumin value in the Nyrami app and see which category it belongs to, explained in words. You can follow it over time together with eGFR and blood pressure, which is what your doctor looks at. The app is free for iPhone and Android.
Turns the advice into something you can use in the shop and the kitchen: scan food and see potassium, phosphorus and salt assessed for you, and follow your numbers over time. Free on iPhone and Android.
In young adults, eGFR is usually above 90, often around 100 to 115, and it falls gradually with age. An eGFR between 60 and 89 is common in older people and does not mean kidney disease on its own. If eGFR stays below 60 for more than three months, it counts as chronic kidney disease (CKD), whatever your age.
Kidney disease rarely causes early symptoms, so it is found with two simple tests: a blood test that shows eGFR and a urine test that measures albumin (uACR). If you have diabetes, high blood pressure, heart or blood vessel disease, or kidney failure in the family, ask your GP for both, ideally every year.
Normal blood creatinine is 45 to 90 µmol/l for adult women and 60 to 105 µmol/l for adult men. High creatinine can mean reduced kidney function, but it can also come from a lot of muscle, creatine supplements, a large meat meal, dehydration or certain medicines. What the number means for you depends on your age and sex.
