Not yet recruitingOBSERVATIONAL

The Practicality and Utility of Measured vs Estimated GFR in adCKD

This study aims to discover if new methods of measuring kidney function are better at predicting when people with advanced kidney disease might start feeling very unwell and need dialysis. It also checks if these new measurements work well for those already on dialysis. Researchers will compare a special test using a dye called iohexol, which helps measure how well kidneys are filtering, against standard kidney function tests. Participants will have a brief health check, receive an injection of iohexol, and provide five small blood samples from a finger over 24 hours. They will also share their thoughts on the experience through a questionnaire. The results could help doctors decide the best time for patients to start dialysis.

At a glance

Status

Not yet recruiting

Sponsor

Manchester University NHS Foundation Trust

Enrolment target

150

Start

01 Feb 2026

Estimated completion

01 Feb 2027

Chronic Kidney Disease (Stages 4 and 5)Chronic Kidney Disease 5D

What is this study about?

This study is for adults with advanced kidney disease, whether they are receiving dialysis or not, who are treated at Manchester Foundation Trust. The main goal is to find out if a new way of measuring how well your kidneys are working, using a special dye called iohexol, is better and more accurate than current tests. The researchers want to see if this new test can help predict when someone with kidney disease might start feeling very unwell and need to begin dialysis treatment. They also want to check if this test can accurately measure the remaining kidney function in people who are already on dialysis but still produce some urine.

The findings from this study could be really important. If the iohexol test proves to be more accurate, it could help doctors make better decisions about when to start dialysis. This might improve how patients with advanced kidney disease are cared for, potentially leading to a better quality of life. The study aims to gather information from 150 people in total, including those with advanced kidney disease not yet on dialysis, people using peritoneal dialysis, and those on haemodialysis who still have some kidney function.

Taking part in this study means you would be contributing to a better understanding of kidney disease and its treatment. While no definite medical recommendations will be made from this study, the results could shape future care by giving doctors more precise tools to manage kidney health. The study focuses on observational data, meaning researchers will carefully watch and record information without introducing new treatments or procedures beyond the iohexol test.

Key takeaways

A study looking at new ways to measure kidney function more accurately.
Aims to predict when people might need dialysis or how well kidneys work on dialysis.
Involves a safe dye injection and finger-prick blood tests.
Participation includes completing a questionnaire about your experience.
Your regular medical care will continue unchanged.

Who may be eligible?

This study is looking for adults aged 18 or older who are able to understand what is involved and give their permission to take part. You might be suitable if you have advanced kidney disease and are expected to need dialysis or a kidney transplant in the next six months. You could also be eligible if you are already having dialysis (either haemodialysis or peritoneal dialysis) and still produce more than 100ml (about half a cup) of urine each day.

However, some things would mean you can't take part. You cannot join if you are under 18, allergic to iodine dyes, or if you can't do the finger-prick blood tests required. You also can't participate if you have temporary kidney problems that are expected to get better, or if you are pregnant or breastfeeding.

Also, if you are due to have a kidney transplant within one month and are not yet on dialysis, or if you have a lot of extra fluid in your body (like swelling in your legs or tummy fluid making you more than 10kg heavier than your normal dry weight), you wouldn't be able to join this study.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you 18 years old or older?
Can you give your permission to join in English?
Do you have advanced kidney disease or are you on dialysis with some urine production?
Are you able to do finger-prick blood tests?
Are you not pregnant or breastfeeding?

Answer every question to see your result.

What does participation involve?

If you decide to take part, you'll have up to three sets of tests, depending on your stage of kidney disease. Each set of tests will happen during a planned visit to the hospital, usually alongside your regular appointments, so there won't be any extra hospital trips just for the study. If you're on haemodialysis, samples will be taken over two consecutive visits.

During these visits, a research team member will briefly check your health and confirm your medical background. You'll receive an injection of a special dye called iohexol, which helps measure your kidney function safely. Over the next 24 hours, you'll need to do four finger-prick blood tests yourself at home, making sure to note the exact time of each test. You can then return these blood samples either in person or by post.

At some point, you'll also be asked to fill out a questionnaire to share your experience of taking part in the study. You might be asked to repeat these measurements again if your kidney disease gets worse or after you start dialysis, to see how consistent the tests are over time.

Potential risks and benefits

Participating in this study might offer the benefit of learning more about your own kidney function, and your involvement will help doctors improve care for other patients with kidney disease. The main risks involve the iohexol injection, which is generally safe but carries a small chance of an allergic reaction. There's also some discomfort from the finger-prick blood tests. Remember, you can choose to leave the study at any time, for any reason, without it affecting your usual medical care.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

Manchester Royal infirmary
Verified postcode
Manchester, United Kingdom

Common questions

What is iohexol?

Iohexol is a special dye that doctors can use to measure how well your kidneys are making your blood clean. It's usually safe and only used in small amounts.

Will I have to pay to be part of the study?

No, you will not have to pay for any part of the study. All tests and appointments related to the study are freely provided.

How long will I be in the study?

The study involves up to three sets of tests. Each set of tests is done over about 24 hours, alongside your regular appointments. The total time you're involved depends on your kidney disease progression.

Will I get my test results?

The study team will not usually share individual research results directly, but the overall findings will help improve care for people with kidney disease.

Can my usual doctor still look after me?

Absolutely. You will continue to receive all your usual medical care from your own doctors and nurses during the study.

How to find out more

Thomas Lindsay, MBChB

thomas.lindsay@mft.nhs.uk +44 161 276 4370 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.