The Practicality and Utility of Measured vs Estimated GFR in adCKD

NCT07450534 | Not Yet Recruiting

• 3 other identifiers: B0235834396470462
• Study Type: observational
• Target: 150
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this observational study is to assess if new ways of measuring kidney function can better predict when individuals will become symptomatic due to kidney failure, and whether residual kidney function can be accurately measured in those already on dialysis. The main questions the study is trying to answer is whether measuring kidney function by clearance of iohexol is comparable to the current standard of care methods. In addition to routine care, participants will:

• undergo a brief clinical assessment
• be given an injection of iohexol and asked to perform 4 finger prick blood tests over 24 hours, recording the time of each sample. Samples will be returned in person or posted back
• be asked to complete a questionnaire on their experience

Conditions

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

Keywords

mGFR; iohexol; Residual Kidney Function

Outcome Measures

Primary Outcomes (4)

• Iohexol measured glomerular filtration rate

  Serial timed dried blood samples taken over 24 hours after injection of iohexol will be tested for iohexol concentration. The measured glomerular filtration rate will be calculated by the rate of clearance (the area under the curve for concentration vs time plot) and corrected for body surface area (derived by weight and height) to give a value in ml/min/1.73m\^2

  Assessed at each study visit through study completion, up to 6 months.

• Creatinine based estimated glomerular filtration rate (Standard of care measure for kidney function in those not receiving renal replacement therapy)

  Serum creatinine concentration (micromoles/liter) will be measured from a venous blood sample. This concentration along with participant age and sex will be used to calculate estimated glomerular filtration rate, corrected for body surface area, from internationally validated mathematical equations. Resuilts are reported in ml/min/1.73m\^2

  Assessed at each study visit while the participant has not yet started renal replacement therapy through study completion, up to 6 months.

• Creatinine clearance corrected for body surface area (Standard of care measure for kidney function in those receiving peritoneal dialysis)

  Creatinine clearance will be calculated from paired blood (serum creatinine concentration) and 24 hour urine (urine creatinine concentration and volume) using validated mathematical equations. This will be corrected for body surface area (derived by weight and height) to give a value in ml/min/1.73m\^2

  Assessed at any study visit where the participant is established on peritoneal dialysis through to study completion, usually 48 hours after this visit.

• Residual renal clearance of creatinine and urea (Standard of care measure for kidney function in those receiving haemodialysis)

  Renal function in haemodialysis can be derived from averaging the measured creatinine and urea clearance. This is calculated using internationally validated equations and requires multiple measurements. This includes: Pre- and post- dialyisis serum creatinine \& urea concentrations from 1st dialysis visit; timed urine collection between dialysis periods measured for urine creatinine and urea concentration, volume, time of collection and time between end of dialysis visit and starting urine collection; And predialsyis serum creatinine and urea from subsequent (2nd) dialysis session. This will be corrected for body surface area (derived by weight and height) to give a value in ml/min/1.73m\^2

  Assessed at any study visit where the participant is established on haemodialysis dialysis through to study completion, usually 48 hours after this visit.

Secondary Outcomes (6)

• Patient acceptability of performing measured GFR as assessed by participant questionnaire

  24 hours. The questionnaire should take no more than 5 minutes but requires completion of the participant's first 24 hour mGFR testing to be done.

• Number of iohexol finger prick samples correctly returned

  Assessed at each study visit through study completion, up to 6 months.

• Single sample iohexol measured GFR

  Assessed at each study visit through study completion, up to 6 months.

• eGFR calculated by novel markers

  Assessed at each study visit through study completion, up to 6 months.

• Presence of uraemic syndrome

  Assessed at each study visit through study completion, up to 6 months.

Study Arms (3)

Advanced Chronic Kindney Disease expected to need dialysis in the next 6 months

As per study description: individuals with progressive advanced chronic kidney disease. Interventions of interest include iohexol injection and 4x finger prick sample collection; clinical review; questionnaire. Routine blood and urine tests are also of interest.

Diagnostic Test: Iohexol Inj 300 MG/ML Diagnostic aid/agent used to measure glomerular filtration rate (GFR)

End stage kidney disease established on peritoneal dialysis with >100ml / 24hours urine output

As per study description: individuals with established end stage chronic kidney disease undergoing peritoneal dialysis. Interventions of interest include iohexol injection and 4x finger prick sample collection; clinical review; questionnaire. Routine blood, urine and peritoneal fluid tests are also of interest.

Diagnostic Test: Iohexol Inj 300 MG/ML Diagnostic aid/agent used to measure glomerular filtration rate (GFR)

End stage kidney disease established on haemodialysis with >100ml / 24hour urine output

As per study description: individuals with established end stage chronic kidney disease undergoing haemodialysis. Interventions of interest include iohexol injection and 4x finger prick sample collection; clinical review; questionnaire. Routine blood and urine tests are also of interest.

Diagnostic Test: Iohexol Inj 300 MG/ML Diagnostic aid/agent used to measure glomerular filtration rate (GFR)

Interventions

Iohexol Inj 300 MG/ML Diagnostic aid/agent used to measure glomerular filtration rate (GFR) DIAGNOSTIC_TEST

Injection of 3235mg iohexol (equivalent to 5ml Omnipaque 300) followed by serial dried blood spot testing over 24 hours to be measured for iohexol concentration and used to calculate clearance.

Also known as: Omnipaque 300

Advanced Chronic Kindney Disease expected to need dialysis in the next 6 months; End stage kidney disease established on haemodialysis with >100ml / 24hour urine output; End stage kidney disease established on peritoneal dialysis with >100ml / 24hours urine output

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Patients under the care of Manchester Universities NHS Foundation Trust Nephrology Department who meet the above inclusion / exclusion criteria

You may qualify if:

• Adults (18 year s or older)
• Able to give informed consent
• Progressive chronic kidney disease predicted to start renal replacement therapy in the next 6 months OR established on dialysis (either haemodialysis or peritoneal) with residual renal function (Urine output \>100ml/day)

You may not qualify if:

• Under 18 years
• Known allergy to iodinated contrast media
• Unable to perform fingerprick blood testing
• Unable to comply with urine collection
• Unable or unwilling to give informed consent in English
• Acute kidney injury expected to recover renal function
• Pre-dialysis and planned renal transplant within 1 month
• Pregnant or breast feeding
• Significant fluid overload (significant peripheral oedema or ascites AND \>10kg above estimated dry weight)

Sponsors & Collaborators

• Manchester University NHS Foundation Trust: lead

Study Sites (1)

Manchester Royal infirmary

Manchester, M13 9WL, United Kingdom

Location

Biospecimen

Retention: SAMPLES WITHOUT DNA

Frozen plasma, serum and urine samples will be stored.

MeSH Terms

Conditions

Renal Insufficiency, Chronic

Condition Hierarchy (Ancestors)

Renal Insufficiency; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Male Urogenital Diseases; Chronic Disease; Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Officials

• Thomas Lindsay

  Manchester University NHS Foundation Trust

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Thomas Lindsay, MBChB

CONTACT

+44 161 276 4370; thomas.lindsay@mft.nhs.uk

Leonard Ebah, MD/FRCP/PhD

CONTACT

+44 161 276 6748; Leonard.ebah@mft.nhs.uk

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER GOV
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: February 10, 2026
• First Posted: March 4, 2026
• Study Start: February 1, 2026
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): February 1, 2027
• Last Updated: March 4, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, ICF, ANALYTIC CODE
• Time Frame: IPD will be available 6 months after first peer review article publication and requests for access will be considered for up to 5 years, while archived data is held. The study protocol will be made available at the time of any article publication. Analytical code may be shared on appropriate request.
• Access Criteria: Qualified researchers with an interest the subject may apply for access to IPD. Planned analysis of the data should be submitted with any request and reviewed by Manchester Foundation Trust Research and Development Team. Approval of the request and execution of all applicable agreements are prerequisites to the sharing of data with the requesting party.

Locations

GB (1)