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Kidney health

Diagnosing problems with kidney health

Blood and urine tests to measure kidney performance

Kidney performance can be calculated from measurements taken on blood and urine samples. A waste product called creatinine is measured in the blood, and urine is checked for the presence of protein. The creatinine level is converted into a measure of how efficiently the kidneys are filtering the blood. For more detail see. ‘How and why is kidney function monitored?’ These measurements can vary over time, so a diagnosis of chronic kidney disease or impairment is made on the basis of repeated blood and urine tests over a three month period showing consistent results rather than a single test.
 

John had three tests in a row that showed his kidney function was dropping, so he was diagnosed with chronic kidney disease; his kidney function has since improved through controlling his blood pressure.

John had three tests in a row that showed his kidney function was dropping, so he was diagnosed with chronic kidney disease; his kidney function has since improved through controlling his blood pressure.

Age at interview: 75
Sex: Male
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And now tell me in a bit more detail about how the kidney came into the picture.

Because they give you a general blood test, which picks up all the other functions and that was one they- they decided that the kidney function was… getting lower and lower.

And can you tell me, did you have a series of tests when that was discovered or?

No, only just the previous two, were obviously, were lowish and then getting lower. So he sent for me and he gave me another blood test… which was still low, which meant, you know, three blood tests on the trot meant that you had chronic kidney disease.

But then they got the blood pressure under control… and the kidney function improved.
 
Following diagnosis, regular blood and urine tests are used to monitor the kidney performance of people who have been diagnosed with mild or moderately impaired performance or early stage chronic kidney disease (see ‘Tests used to monitor kidney health’).

Diagnostic tests for underlying causes of kidney impairment

Impaired kidney performance can be caused by a variety of things, such as having diabetes or high blood pressure, or a structural problem with the kidneys, such as a blockage, and is more common in older people. Some people we spoke to had tests done to try to identify any underlying structural problems with the kidneys. These included an ultrasound scan, biopsy, urine flow test, or intravenous pyelogram (IVP) (see below). Not many people with early stage kidney impairment need these tests, nor are they used for regular monitoring of early stage chronic kidney disease.

An ultrasound scan uses sound waves to create an image of a part of the body, in this case the kidney. As no radiation is used in the procedure it is perfectly safe and is commonly used in pregnancy to see the developing baby. It is necessary to drink a lot of water before the scan to fill the bladder. A lubricating jelly is put on the skin and a handheld probe moved over the part of the body being examined and the pictures can be seen on a screen. The scan is conducted by a specialist technician called a sonographer.
 

Robert was alarmed at first that his doctor wanted a scan of his kidneys but was later reassured. He found having the scan itself interesting.

Robert was alarmed at first that his doctor wanted a scan of his kidneys but was later reassured. He found having the scan itself interesting.

Age at interview: 70
Sex: Male
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Well obviously when a doctor says to you that …wants you to go and have a kidney scan, you think- think to yourself, 'Oh blimey what does he know that he's not telling me?' So I asked him that question and he said, "Don’t be silly," he said, "it's nothing but we want to be on the safe side and check you out." And that’s basically on that basis so when he said that I wasn’t that worried. Well you either trust your GP or you don’t and some people get hysterical about it but , you know, these people are basically there to help you; they're not there to try and trick you or anything.

Oh it's very interesting. You go to the hospital, then you go into this room. There's a lady with a machine. She asks you to expose your stomach – I thought she was going to kiss my tummy, but no. And then they put a gel on and it's… I suppose it's what they do with ladies who are having a baby, they, you know, that scan. And she pushed and prodded and, you know, all the rest of it and twiddled her knobs and dialled her dials and then she… the screen that she was looking at was slightly to one side and she was taking photographs at the same time, and what amazed me was the fact that a kidney looks exactly like a kidney dish. I suppose that’s why they call it a kidney dish but, you know, I thought there'd be some massive lump of machinery going away and… that was very interesting, to me anyway.

Mm so you were able to see the image as you were being scanned?

Yes, well not totally face on but it was… she was, you know, slightly to the side of me.

Yeh

And she had one hand here and the screen like that and I could just see what was going in – very, very interesting I thought.
 
 

It took Sarah longer than average to fill her bladder in preparation for an ultrasound scan of her kidneys; the sonographer asked her twice to return to the waiting room.

It took Sarah longer than average to fill her bladder in preparation for an ultrasound scan of her kidneys; the sonographer asked her twice to return to the waiting room.

Age at interview: 77
Sex: Female
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Well I thought there was something wrong because she had tried to do it about three times, because I had to drink a lot of water, as you know, beforehand. So about 7 o’clock I drank all they suggested, went to the hospital. They weren’t in much of a hurry, so I was getting a bit cross. But eventually when she started the scan she said, ‘Your bladder hasn’t filled enough. Have you done what we asked you? ’ She was a bit stern, and I said, ‘Yes I have done what you asked me’. And so she told me to wait a bit longer in the waiting room for 20 minutes, drink a bit more, and then when I went back she still couldn’t do it. She said, ‘It hadn’t cleared into my…’ whatever it was, for my kidneys, and she was extremely nice then and said, ‘Would you mind very much waiting a little bit longer. This is not working. It’s not satisfactory. We’d like you to wait a little longer, and are you comfortable?’ And she was very solicitous then and very nice. And I said, ‘Does this happen often?’ And she said, ‘Oh sometimes’. She said, ‘One lady a few weeks ago we had to wait two hours’. So I said, ‘Well isn’t that an indication of something wrong?’ And she said, ‘Not necessarily’. So when I asked the doctor, they said, ‘No some people are just like that’. But I just wondered.

You thought it was an indication that your kidneys were working slowly or something?

Yes I thought there was an indication but they said it wasn’t relevant at all, when I questioned them. So maybe that’s an area for research.
 

Xanthe had lost one kidney to cancer many years ago, so when she learned recently that there was a new problem with her kidney function she asked for a scan of her remaining kidney to check the cancer had not returned; the scan results looked normal. Jackie has had damaged kidney function since childhood and when she recently moved to a new general practice the doctor arranged an ultrasound scan to provide a new baseline image of her kidneys. During her childhood a different type of scan had been used, called an intravenous pyelogram (IVP), which is a special x-ray examination of the kidneys, bladder, and ureters (the tubes that carry urine from the kidneys to the bladder) using a special dye. This tests how well the kidneys remove the dye and how it collects in the urine. She also recalls having a urine flow test (see below).
 

Jackie has had different types of imaging of her kidneys since childhood plus urine flow tests. She describes what it was like to have an intravenous pyelogram.

Jackie has had different types of imaging of her kidneys since childhood plus urine flow tests. She describes what it was like to have an intravenous pyelogram.

Age at interview: 59
Sex: Female
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The other thing that happened recently was I did have an ultrasound scan of my kidneys , and that again was the GP that I’m currently seeing wanted to just get a baseline of where things were at because I hadn’t had any sort of investigations for a long time. Used to be IVPs where they put the dye in and… But anyway I just had an ultrasound scan, which was more pleasant than having IVP [laughs].

What’s an IVP?

That’s an intravenous pyleogram, where you have dye put in and they monitor it going through your kidneys.

So you’ve had those before?

[mm]

Have you had them often?

I had, I had several when I was a child, once, then I had, I had them more regularly when I was younger and then I think prior to becoming pregnant the first time, and again that was about getting baseline information to see how my kidneys might function during pregnancy. And I also had a, I don’t know what’s that called, a sort of where they monitor, where your bladder is full and you, you know, it sees how your kidneys function and release the your urine but I can’t remember what that was called. When I had the, but then I think I had, in my adult life, I think I might have had one or two, not very often, no.

So what’s unpleasant about having the IVP?

Oh it’s just that you feel the dye going round your body.

Okay.

You know, it goes, it goes in from your arm and you actually feel it going up right through every everything, and so you get a hot feeling going through your, through your body and they put, I don’t know whether they still do this, but they used to put tennis balls on your stomach and tighten a belt really tight across, and it was something to do with restricting, I don’t know what it was, but it was restricting the dye or keeping the dye in your bladder or… I don’t know, I can’t I can’t remember.
 
Several people mentioned having a urine flow test, known as a urodynamic test. This involves measuring how much urine leaves the bladder over a certain length of time and taking pressure readings from the bladder and abdomen while the bladder is filled and emptied. Some also had a cystoscopy – insertion of a thin tube into the bladder with a camera on the end.
 

Mike had blood in his urine and as part of his diagnostic investigations had a camera inserted into his bladder to examine it, as well as a urine flow test. The results of both tests were normal.

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Mike had blood in his urine and as part of his diagnostic investigations had a camera inserted into his bladder to examine it, as well as a urine flow test. The results of both tests were normal.

Age at interview: 36
Sex: Male
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I did have a camera… look in my bladder. That and a… [in response to interviewer looking surprised] yeah exactly yeah [slight laugh]…

[laughs]

And a flow test, a urine flow test , …so yeah I've had those, that sort of thing done, but nothing, …no sort of scan or anything like that no, no.

Would you be prepared to describe that in a bit more detail because it sounds , how does that actually work, that sort of investigation?

A camera is put in your penis and looked up inside the bladder.

Mm

And that, yeah, that’s as painful as it sounds, yeah. So that was , that’s what I had done yeah.

Were you conscious at the time or did you have an anaesthetic?

Yeah, no, no. There was anaesthetic used I'm sure yeah, yeah but, you know, it's extremely uncomfortable.

Mm

And I wouldn’t want to do it… my eyes are watering now thinking about it again [laughs]. So yeah it was extremely uncomfortable but the… it was needed to do because of the… I was having discomfort urinating and… it was all part of the same, you know, in the same thing, to eliminate potential problems for the blood in the urine, you know? So yeah so that was that, and the flow test you wee into a special contraption on a… that’s fixed to a toilet and it measures the rate that you can urinate at. So if you’ve got restrictions yeah.

[laughs] Sounds like a competitive… sorry, it sounds like something you can use for competition.

Well yeah I suppose you could reg… [laughs] you know, record the speed and yeah and do it that way. So- but there was nothing, with either of those there was no problem, you know, there was no issue.
 
A kidney biopsy involves the removal of a small sample of tissue from the kidney using a hollow needle and sometimes guided by an ultrasound scanner. The area is first numbed with a local anaesthetic so there should be no pain. The tissue sample can then be examined under the microscope or examined in other ways.

Justine’s chronic kidney disease is caused by a condition called IgA nephropathy, which was diagnosed through having a biopsy. She was initially quite worried about having a biopsy and wanted a lot of information about what it would involve before having it. She felt more alarmed by the prospect of having to lie still for six hours afterwards than by the insertion of the needle itself. The first time she went to the hospital the procedure was cancelled because she had taken aspirin the previous evening for a headache - caused by anxiety about having the procedure - and was told the aspirin could cause internal bleeding at the biopsy site. She went back two weeks later and had to wait several hours for a bed to become available so the biopsy could be done. Three samples were taken. It was late at night before she was able to go home; she felt stiff and bruised for a few days afterwards.
 

Justine describes what it was like having kidney biopsies taken.

Justine describes what it was like having kidney biopsies taken.

Age at interview: 44
Sex: Female
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And they eventually said, "Right," - four o'clock – "right we can do it." …So I walked down to this room with the doctor and a nurse and… I laid face down on a bed, …I put a gown on- I had my jeans on but I still had a gown on because obviously they just needed to get to my lower back.

And they have a scanner there so she scanned – it's like an ultrasound scanner – and you can see the kidneys on the screen and all the- whatever it is you look at, they look at. And she said I could watch it if I wanted. I said, "No [exhales] you're alright." And she explained what she was going to do. And then she gave me the first injection which obviously you felt the needle go in, and then after that I didn’t feel anything at all after that. Then she put about three injections in to numb it up right down through to the kidneys. And then she said, "Oh," she said, "you'll hear a clicking sound when I take…" and she showed, told me that then… showed me the signs… showed me the signs? That doesn’t make sense. She clicked the needle or whatever it is to take the biopsy and so I'd hear- know what it sounded like. I said, "OK fine."

Anyway so she put the needle in and I didn’t feel a thing. She said, "But I when I take… go to take it," she said… because where I'm breathing the kidneys are going up and down. And she said, "I want you to hold your breath to hold the kidneys steady," she'll click it, take the biopsy and then I can breathe again [laughs]. I said, "OK fine." So as I… so she said, "Right take a breath," so I took a breath. And she went like that [makes clicking sound] and I actually… felt it? I felt it, does that make sense?

Yeah

Whether it was psychologically felt or felt I don’t know.

You felt like a tugging?

Yeah a little tug. …Wasn’t painful, it was just like yeah, like a tug I suppose that’s the right word for it. And she turned round, she said, "Ooh," she said, "I've got a bit of the muscle as well as the kidney," she said, "I will do it again." I said, "OK no worries." So she took it again. So she said, "Oh that’s better," she said, "I'll take one more for luck." [laughs] I went, "OK [laughs] ha ha ha thanks!" So she took another sample, so I ended up with three little samples. I said, "OK fine," I said, "I'd rather you get it now than having to come back and do it all again." [laughs] …So that’s fine and… so she said, "Right," and then she obviously took the needle out and cleaned up and she put a little… just like a little Melolin plaster thing over it. And she said, "Right," she said, "It's alright," she said, "I want you to turn over." So she said, "But I don’t want you to do anything," she said, "I will…" the nurse and doctor, she said, "I will move you, I don’t want you to move yourself," and of course I tried to move myself aren't I? as you do [coughs]. Excuse me. And so they moved… turned me on with my back and she said, "Right," she said, "we're going to take you up to the ward." I said, "OK fine." So they then took me in the lift up to the wards to the bed and they then had to put me from the trolley onto the bed. and they got one of those boards that pull you across that you have to lie on?

Hm mm

And she said, "Right," and there was about three or four of the nurses around me at this point. She said, "Right," she said, "I don’t want you to do anything," she said, "just let us do all the work, just lie there," because you're not allowed to move… because it could… by moving because where they’ve taken it out, the kidney needs time to repair itself and the clot because otherwise it could bleed.

Mm

And so they literally dragged me across onto the bed… and I just had to lie there flat and that was it and she said… and I said, "Can I have a drink and that?" So she'd get me some water and things. And that was it! I was just literally laid there, I couldn’t… I was staring at the ceiling, trying to look around [laughs] and trying to see what else was going on in the ward because I think there was about three or four other people in the ward as well, and then just listening to what was going on around me really [laughs].
 
Laura’s doctors suspect that she also has IgA nephropathy but they don’t know for certain because she decided not to have a kidney biopsy. She didn’t want a small piece of tissue removed for examination as she was afraid her kidney might not heal fully afterwards. Healing is not usually a problem after a kidney biopsy but there is a risk of bleeding. A kidney biopsy will only be conducted if the benefits are considered to outweigh the risks.

Last reviewed August 2017.
 
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