Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT01403766 |
| Other study ID # |
Gentian-Cystatin-UCLA |
| Secondary ID |
|
| Status |
Completed |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
August 2011 |
| Est. completion date |
December 2012 |
Study information
| Verified date |
November 2020 |
| Source |
University of California, Los Angeles |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational
|
Clinical Trial Summary
Glomerular filtration rate (GFR) is the best known measurement of kidney function. Serum
creatinine (blood test) is the most commonly used marker to predict GFR. It is a convenient,
inexpensive test that involves a single blood draw with rapid results. However, creatinine
has several limitations because its blood level is dependent on age, body mass, and sex. One
of the gold standards for measuring GFR is plasma clearance of an IV injected agent, iohexol.
It has been found to be safe and nontoxic in prior studies, but is not practical in the
clinical setting due to the need for several timed blood draws. Recent studies have
investigated the use of cystatin C as an alternative marker to predict GFR. Cystatin C also
involves only a single blood draw, and has less confounding factors than creatinine since it
is independent of age, body mass, and sex. Currently, it remains controversial whether
cystatin C is a significantly better biomarker of estimated GFR than creatinine. To date,
there has not been a large prospective cohort study to compare cystatin C and creatinine in
pediatric kidney transplant patients who are on maintenance immunosuppression (anti-rejection
drugs). Accurate measurement and early detection of deterioration of GFR is critical in the
care of this patient population. The purpose of this study is to assess the accuracy of
estimating GFR by using cystatin C versus creatinine clearance equations when compared to the
surrogate gold standard of iohexol GFR in pediatric renal transplant patients.
Description:
Study patients will come in for their surveillance biopsy done as standard of care
post-transplant. They we be made NPO at midnight prior to the biopsy per routine. On arrival,
they will have standard of care pre-biopsy bloods drawn along with baseline study labs
including serum enzymatic creatinine (1mL of blood), cystatin C (1.5 mL of blood), and 1mL of
blood collected pre-iohexol infusion. Two IV's will be started, one for iohexol
administration and fluids, and the other for blood draws. Study patients will be started on
1x maintenance intravenous fluids. The patient will then have their standard of care protocol
biopsy in the ultrasound suite. After the biopsy 5 mL Iohexol (Omnipaque 300) will be
administered over 1-2 minutes, with epinephrine, solumedrol, and diphenhydramine on hand in
the event of a reaction although this is very unlikely. The patient will be observed and
vital signs will be taken 10 minutes post-infusion. After biopsy, maintenance fluids will be
continued until completion of the study. Blood for determination of Iohexol levels (1mL) will
be drawn at 10, 30, 120, and 300 minutes post iohexol infusion when patient is being observed
post biopsy. At completion of the study at 300 minutes post iohexol infusion, serum
creatinine (1mL of blood), cystatin C (1.5 mL of blood) will be drawn again. The total volume
of blood drawn for the study will be 10mL.
Creatinine (enzymatic method) will be determined on the Olympus system, and Cystatin C
(Gentian assay) will be determined on the AU400 Olympus System at the UCLA Department of
Pathology and Laboratory Medicine Outreach Laboratory. Iohexol GFR will be determined at the
University of Rochester Medical Center in Dr. Schwartz's laboratory. Kidney biopsies will be
graded by updated Banff criteria, and reviewed by blinded pathologist.
