Blood in urine
Blood in urine almost never hurts. That is exactly why it is so easy to write off: the urine turns pink once, the next day it is normal again, nothing is…
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Medicines commonly prescribed for Blood in urine
For informational purposes only. Always consult a doctor before taking any medication.
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Blood in urine almost never hurts. That is exactly why it is so easy to write off: the urine turns pink once, the next day it is normal again, nothing is troubling you, and you conclude it was nothing. It was not nothing. Visible blood in urine is always a reason to see a doctor and be investigated, even if it happened once and cleared up by itself. Below is why we are so firm about this, what causes it, what colours urine without being blood, and when you cannot even wait until morning.
Why a single episode still has to be checked
There are many causes of blood in urine and most of them are not dangerous. But this is precisely how bladder cancer and kidney cancer announce themselves: painless, discoloured urine, once, gone on its own. At an early stage they give no other sign at all — no pain, no difficulty passing urine, no temperature, and you feel perfectly well. Blood is the only signal they send, and they send it rarely.
Hence a rule that sounds harsher than we would like: the bleeding stopping does not mean the cause has gone. A bladder tumour bleeds intermittently — blood today, none a week later, and then it turns up again two months on. The gap without blood is not recovery, it is a pause.
The investigation almost always ends in good news, and that is the whole point: a bladder tumour found early can be treated, and one found late does far worse. The difference between those two outcomes is one appointment.
You also need to be seen if you take blood-thinning medicines. A common mistake is to think "it is the tablets". Those medicines do not create bleeding out of nothing; they make visible something that was already there. The investigation is needed just the same.
What it looks like, and when it is not blood
Urine with blood in it may be pink, the colour of washing-up water from meat, red, or brown like strong tea or cola. Brown usually means the blood is coming from the kidney and has altered on the way down; bright red means the source is lower, in the bladder or the urethra. Sometimes clots are visible, and sometimes the blood appears only at the start or only at the end of passing urine.
But red urine is not always blood. It is also coloured by:
- beetroot, blackberries, rhubarb and foods containing red colourings;
- medicines — certain antibiotics, antimicrobials and laxatives, and some drugs for bladder pain. Where a medicine has that effect, it is stated in the patient leaflet;
- menstrual blood mixing with the urine;
- bleeding from the back passage, seen in the toilet bowl and taken for blood in the urine.
Three things help tell them apart. Food or drug colouring stays an even shade from the start of the stream to the end, and fades a day or two after you stop the food or the medicine. Blood is more often uneven, may form clots, and comes back with no relation to what you have eaten. And the most reliable of all: a urine test answers the question in minutes. Until it is tested, treat it as blood — erring that way costs nothing, erring the other way costs time.
What is usually behind it
Other symptoms, if there are any, point the search in a direction — but only point: they do not make the diagnosis.
- A urinary tract infection. Burning or stinging on passing urine, going often, a feeling of not emptying fully, cloudy urine with a strong smell. Add a high temperature, shivering and loin pain and the infection has climbed to the kidney, which is urgent;
- a stone. Severe pain in the side coming in waves and running down towards the groin; the person cannot find a position that helps and often feels sick. The stone scrapes the wall of the ureter, and that is where the blood comes from;
- an enlarged prostate. In older men: a weak stream, having to strain, a delay before the flow starts, getting up at night to pass urine;
- injury. A blow to the loin or the abdomen, a fall, a road accident — the blood can appear hours later;
- physical exertion. After a long run or a hard training session urine sometimes darkens, and this settles within a day or two. It is the one innocent cause on this list, but there is only one way to confirm it after the fact — repeating the test after rest. If the blood is still there, exertion was not the answer;
- disease of the kidney itself, such as inflammation of the filtering units. Cola-coloured urine, puffiness under the eyes and in the legs, raised blood pressure, and plenty of protein alongside the blood in the test;
- less often, kidney cysts and congenital variants, clotting disorders, inherited blood conditions, and — in people who have swum in fresh water in Africa — a parasitic infection of the bladder.
Blood that only shows up in the test
The opposite also happens: the urine looks normal, and the test finds red blood cells. This is called hidden, or microscopic, blood in the urine, and it is usually picked up by chance at a check-up, before an operation, or during tests done for something else.
The level of concern here is lower than with visible blood, but it is not zero. First the test is repeated: a one-off finding can follow exertion, a period, a fever or a catheter. If the blood persists, the doctor looks at whether there is protein in the urine as well, whether kidney function is affected and whether blood pressure is up — that combination points to kidney disease and leads to a kidney specialist. If there is no protein but there are risk factors — age, smoking, work with dyes, rubbers and solvents — the urinary tract is investigated exactly as it would be for visible blood.
When it is an emergency
Call an ambulance (in Spain, Italy, Portugal, Poland and Ukraine the single number is 112) if:
- there are clots in the urine and you cannot pass urine at all — a clot has blocked the outlet, and the bladder is full and painful. This is an emergency and is dealt with in hospital with a catheter;
- the bleeding is heavy and there is weakness, dizziness, pallor, cold sweat or a racing heart, which are signs of blood loss;
- the blood has appeared after a heavy blow to the loin or abdomen, after a fall or a road accident;
- along with the blood there is a high temperature with shivering, loin pain and confusion — this is what a kidney infection turning into blood poisoning looks like.
Get seen the same day, without waiting for a routine appointment, if the blood comes with a temperature, pain in the loin or side, if you can pass urine but only with difficulty, or if you take blood-thinning medicines. In every other case a routine appointment is right — but an appointment, not watching and waiting at home.
How it is investigated
The work-up runs from simple to complex, and the first steps are quick:
- a urine test, which confirms it really is blood and shows protein, white cells and other traces; a urine culture is added if infection is suspected;
- blood tests: a full blood count, kidney function and, if needed, clotting. In men a PSA is added depending on age and symptoms;
- a blood pressure reading — pressure is both a cause and a consequence of kidney disease;
- an ultrasound scan of the kidneys and bladder and, with visible blood, often a CT scan with contrast, which shows the kidneys and ureters in more detail;
- a look inside the bladder with a thin flexible instrument. It is done under local anaesthetic and takes a few minutes; it is the only way to see the bladder lining, because early tumours there do not show on scans.
If an infection is found and treated, the urine test is repeated after the course. Blood still present once the infection has been cured means investigating further, not treating again. Nor is it a good idea to start antibiotics yourself on an old prescription: they will settle the symptoms, the blood will go unnoticed, and the time will be lost.
What happens once the cause is found
There is no treatment "for blood in urine" — what gets treated is whatever caused it. Infection is managed with antibiotics chosen for the organism. Small stones pass on their own with plenty of fluids and pain relief; large ones are broken up or removed. For an enlarged prostate there are medicines that shrink it and ease the flow, and surgery is offered if they are not enough. Kidney disease is looked after by a kidney specialist, where controlling blood pressure and protein in the urine comes first.
If the investigation finds nothing — and that is a common outcome — you are not discharged for good. The usual plan is a repeat urine test a few months later, with a request to come straight back if the blood returns. This is not excessive caution: some findings only become visible the second time round.
Online consultation
In an online consultation the doctor goes through your case properly: what colour the urine was, whether the blood came at the start or the end of the stream, whether there were clots, what you have eaten and what medicines you take, whether there is pain, a temperature or an injury. They will tell you plainly what needs an ambulance, what needs to be seen today and what can wait for a routine appointment, and which tests are worth having done before you see a urologist so that you do not go twice. They will read any results and scans you already have, explain what the findings mean, and help you keep hold of the main point: blood that stopped on its own still needs an explanation.
This material is for information only and does not replace medical advice.
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