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A new study by Alwasiyah et al. concluded that the current reference range of 0.7 μg/24hr for 24-hour urinary gadolinium is not applicable to patients for at least 30 days following exposure to a gadolinium-based contrast agent (GBCA). In the study, the authors “calculated an estimated average of 57 days for the urinary gadolinium to creatinine ratio to reach below the current reference range following GBCA exposure and possibly much longer (i.e., 80+ days)”. The article, “Urinary Gadolinium Levels After Contrast-Enhanced MRI in Individuals with Normal Renal Function: a Pilot Study”, was published online December 12, 2018 in the Journal of Medical Toxicology.
This was a prospective, observational pilot study to determine urine gadolinium concentrations over a 30-day period after GBCA administration in patients with normal renal function. The 13 subjects were between 18 and 65 years of age and were reported to have received a gadolinium-based contrast agent for the first time. Prior to contrast administration, spot urine samples were obtained and tested for gadolinium and creatinine. All testing was performed by Mayo Medical Laboratories in Rochester, MN. Post-MRI 24-hour urine testing was performed on day 3, 10 and 30. Eight subjects received gadobutrol (Gadavist®), four received gadopentetate dimeglumine (Magnevist®), and 1 received gadoxetate disodium (Eovist®) for their MRIs with contrast. The authors reported that all 13 subjects had 24-hour gadolinium levels higher than 0.7 μg/24hr on day 3, day 10, and day 30 after contrast administration. The authors estimated that “urinary gadolinium levels will often remain above the current reference range for >50 days”. (more…)