Comparability of fingerprick vs venous blood for tacrolimus monitoring
Research type
Research Study
Full title
Developing an LC-MS/MS method for measurement of tacrolimus and creatinine concentration from finger-prick blood collected using the Mitra device
IRAS ID
340380
Contact name
Donna Fullerton
Contact email
Sponsor organisation
Nottingham University Hospitals NHS Trust
Clinicaltrials.gov Identifier
Duration of Study in the UK
0 years, 4 months, 28 days
Research summary
Research Summary -
Organ transplant rejection occurs when the immune system attacks the transplanted organ. To prevent rejection, transplant-patients are given immunosuppressant drugs which can suppress the immune system from attacking the transplanted organ. Patients who have had a kidney-transplant take immunosuppressant drugs such as tacrolimus, but the dosage must be closely monitored through regular blood tests to avoid complications like organ failure and kidney damage. The current practice at Nottingham University Hospitals NHS Trust is that kidney-transplant patients being monitored for tacrolimus have regular blood samples taken by venepuncture (vein), and the samples are sent to the laboratory to be measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS), a technique used in chemistry to identify and quantify substances in a sample. Patients will also often have their blood-creatinine measured to get an idea of kidney health. Visits to the GP/hospital for this type of blood collection can be disruptive to a patient’s daily life and stretches resources of the NHS. An alternative blood sample collection process involves the use of a hand-held blood collecting device called a Mitra device, designed to allow patients to collect samples at home through a finger-prick and send them by post for analysis. This method is especially beneficial for those who find hospital visits challenging or venepuncture painful.
This study aims to develop an LC-MS/MS method for measurement of tacrolimus and creatinine, using finger-prick samples collected on the Mitra device. To do this,
kidney-transplant patients who are having routine venepuncture to measure tacrolimus and creatinine will simultaneously have a finger-prick sample collected using the Mitra device. Both samples will be analysed using LC-MS/MS technology but the analytical method may need to be modified due to the smaller sample volume of the finger-prick sample. The results from the finger-prick and venous collected samples will be compared to ensure consistency of results.Lay Summary of Results -
After a kidney transplant, patients often take medication called tacrolimus to prevent their immune system from rejecting the new organ. The concentration of tacrolimus in the blood needs to be closely monitored. Patients that are given too little tacrolimus do not benefit from the medications purpose and their body may still reject the transplanted organ, whereas those given too much tacrolimus can have kidney damage and other side effects associated with the medication. Creatinine is regularly measured in patients taking tacrolimus, as it can be used as a marker of kidney health, with high levels indicating that that the transplanted kidney could be damaged, and that the tacrolimus dose may need to be adjusted.
Nottingham University Hospitals currently measure tacrolimus and creatinine by collecting blood from a vein. This sort of monitoring requires patients to frequently visit the hospital or GP surgery to have their bloods taken, which is time-consuming and inconvenient for patients. To improve the service, this study explored whether a device called the Mitra microsampler could offer a simpler alternative to monitor patients for tacrolimus and creatinine. The device collects a small amount of blood from a finger-prick. Once dried, the sample can be posted to the lab for analysis. If this method was found to be a suitable alternative, it could allow patients to self-collect samples at home, reducing the need for hospital visits. In order to assess this, two new lab tests were developed using a specialised technique called liquid chromatography tandem mass spectrometry (LC-MS/MS). One test measured tacrolimus, whilst the other test measured creatinine. Both tests can be performed from the same finger-prick sample collected on the Mitra device. These tests were assessed to ensure they were accurate and reliable.
The tacrolimus and creatinine tests both worked well and gave accurate results when the correct amount of blood was applied to the Mitra device. However, results from real patient finger-prick samples did not compare well with the tests that are currently used to test tacrolimus and creatinine (which uses blood collected from a vein). The main issue seemed to be that the Mitra device did not always absorb the same amount of blood from the finger-prick. This caused the test results to sometimes be too high or too low, because too much or too little blood was being tested.
In conclusion, the Mitra device was unable to consistently collect the required volume of blood for accurate testing, therefore it is not suitable for use. However, with further improvement or use of an alternative finger-prick collection device that can ensure consistent sample volume, finger-prick sampling could be introduced at Nottingham University Hospitals for the measurement of tacrolimus and creatinine. This would allow patients to collect blood samples remotely and post them directly to the laboratory for analysis. Once measured, changes to doses can be made over the phone in time for the patient to pick up their next dose, avoiding unnecessary hospital appointments and maximising the NHS resources.REC name
London - Hampstead Research Ethics Committee
REC reference
24/PR/1186
Date of REC Opinion
30 Oct 2024
REC opinion
Further Information Favourable Opinion