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Chiu-wen Chen - One of the best experts on this subject based on the ideXlab platform.
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Kinetics of Iohexol degradation by ozonation and formation of DBPs during post-chlorination
Journal of water process engineering, 2020Co-Authors: Du Yifan, Yi-li Lin, Hua Shuangjing, Yuan-zhang Hou, Yan-guo Deng, Zhang Jichen, Ren Sicheng, Cheng-di Dong, Chiu-wen ChenAbstract:Abstract Degradation kinetics of the widely used iodinated X-ray contrast medium, Iohexol, was investigated in this study by ozone advanced oxidation process (AOP). Factors influencing Iohexol degradation, pH, ozone dosage, and the presence of different background ions were also evaluated. Results show that Iohexol degradation during ozonation followed the pseudo-first-order kinetics well; the degradation rate increased with the increase of pH values and reached a maximum of 1.29(±0.05)×10−1 min−1 at pH 9. As the ozone concentration gradually increased from 0.342 to 1.13 mg/L, the corresponding pseudo-first-order rate constant of Iohexol degradation increased from 7.25 (±0.30)×10−3 to 5.77(±0.26)×10−2 min−1. At pH 7, the presence of background ions have different inhibitory effects on Iohexol during ozonation degradation. Br exhibited the strongest inhibitory effect followed by HCO3− and CO32-, while Cl possessed negligible influence. Less disinfection by-products (DBPs) were formed at circumneutral pH values and low bromine concentrations (
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Kinetics and formation of disinfection byproducts during Iohexol chlor(am)ination
Separation and Purification Technology, 2020Co-Authors: Hua Shuangjing, Du Yifan, Yi-li Lin, Yuan-zhang Hou, Yan-guo Deng, Cheng-di Dong, Chiu-wen ChenAbstract:Abstract In this study, the degradation kinetics, and the formation of disinfection byproducts (DBPs) during Iohexol chlor(am)ination were studied. The chlorination kinetics can be described using a second-order model. As the pH of the solution increased, the apparent second-order rate constant of Iohexol chlorination increased considerably. The reaction rate constants of Iohexol with HOCl and OCl− were calculated as ( 3.75 ± 0.70 ) × 10 - 4 and ( 1.39 ± 1.19 ) × 10 - 4 M−1 s−1, respectively. In addition, the chloramination of Iohexol followed tertiary kinetics, and the maximum apparent rate constant of 3.78 × 10 - 6 M−1 s−1 occurred at pH 7. NH4+ can promote the degradation of Iohexol during chlorination, whereas Br− inhibits Iohexol degradation during chloramination. The formation of conventional carbonated DBPs and emerging nitrogenated DBPs during chlor(am)ination of Iohexol was measured. However, in the presence of bromide, the conversion of Iohexol to toxic iodinated DBPs increased significantly during chlorination, and chlorination resulted in higher formation of toxic I-DBP compared to chloramination. Therefore, chloramine disinfection is preferred for treating raw water containing high bromide concentrations in terms of DBP formation control.
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Investigation of Iohexol degradation kinetics by using heat-activated persulfate
Chemical Engineering Journal, 2019Co-Authors: Yuan-zhang Hou, Du Yifan, Yi-li Lin, Hua Shuangjing, Yan-guo Deng, Chiu-wen ChenAbstract:Abstract In this study, we investigated the degradation kinetics of a commonly used iodinated contrast medium, Iohexol, by using heat-activated persulfate. The results indicate that the Iohexol concentration can be effectively reduced with a removal percentage higher than 85% despite the long reaction time (2–3 h). The Iohexol disappearance fitted well with the pseudo-first-order kinetic model. The persulfate consumption almost reached the maximum value during the initial 5 min of the reaction. Subsequently, persulfate was no longer consumed, which resulted in a decrease in the reaction rate. The pseudo-first-order rate constant of Iohexol degradation significantly increased with temperature but decreased with an increase in pH from 5 to 9. The results of the quenching experiments performed using ethanol and tert-butanol indicate that the role of hydroxyl radicals was more important than that of sulfate radicals in Iohexol degradation during heat-activated persulfate oxidation. However, without heat activation, persulfate did not react with Iohexol. Therefore, the effect of pH on the HO· concentration dominated the effect of pH on Iohexol degradation. High concentrations of bicarbonate (≥5 mM), chloride (≥1 mM), and dissolved natural organic matter (≥5 mg/L) inhibited the degradation of Iohexol due to the consumption of sulfate and hydroxyl radicals. The mineralization percentage was only 3.8% (no considerable improvement) when the temperature was increased to 80 °C. The molecular structures of the intermediates contained iodine with molecular weights higher than 377 Da. Moreover, the generation of iodide was detected. The experimental results suggest that special attention should be paid to the risk of the formation of disinfection by-products in the subsequent chlorine disinfection process when treating natural water containing Iohexol through heat-activated persulfate oxidation.
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Kinetics and model development of Iohexol degradation during UV/H2O2 and UV/S2O82− oxidation
Chemosphere, 2019Co-Authors: Yuan-zhang Hou, Du Yifan, Yi-li Lin, Hua Shuangjing, Yan-guo Deng, Chiu-wen ChenAbstract:Abstract The degradation rates and kinetics of one commonly used iodinated contrast medium, Iohexol, were investigated and compared during ultraviolet (UV) photolysis, UV/H2O2 and UV/ S 2 O 8 2 − advanced oxidation processes (AOPs). Results indicate that the Iohexol degradation rate increased in the order of UV/H2O2 S 2 O 8 2 − and followed pseudo-first-order kinetics. Increasing persulfate concentration significantly increased Iohexol degradation rate, whereas increasing H2O2 concentration caused reverse effect. Radical scavenging test results show that UV photolysis, OH and radicals all contributed to Iohexol degradation during UV/ S 2 O 8 2 − , but OH was the main contributor during UV/H2O2 and was consumed by excess H2O2. The kinetic models of Iohexol degradation by both AOPs were developed, and the reaction rate constants with OH and were calculated as 5.73 (±0.02) × 108 and 3.91 (±0.01) × 1010 M−1 s−1, respectively. Iohexol degradation rate remained stable at pH 5–9 during UV irradiation and UV/H2O2, but gradually decreased at pH 5–7 and remained stable at pH 7–9 during UV/ S 2 O 8 2 − . The presence of anions displayed inhibitory effects on Iohexol degradation during UV/ S 2 O 8 2 − in the order of Cl − > HCO 3 − ≫ S O 4 2 − . UV/ S 2 O 8 2 − AOP exhibited high degradation efficiency and stability on the basis of UV irradiation, which can be applied as a promising degradation method for Iohexol. UV/ S 2 O 8 2 − AOP can effectively mineralize Iohexol to CO2 but promoted the generation of toxic iodoform (CHI3), and the subsequent chlorination had the potential to reduce the content of disinfection by-products; therefore, further evaluation of possible environmental hazards is warranted.
Yi-li Lin - One of the best experts on this subject based on the ideXlab platform.
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Kinetics of Iohexol degradation by ozonation and formation of DBPs during post-chlorination
Journal of water process engineering, 2020Co-Authors: Du Yifan, Yi-li Lin, Hua Shuangjing, Yuan-zhang Hou, Yan-guo Deng, Zhang Jichen, Ren Sicheng, Cheng-di Dong, Chiu-wen ChenAbstract:Abstract Degradation kinetics of the widely used iodinated X-ray contrast medium, Iohexol, was investigated in this study by ozone advanced oxidation process (AOP). Factors influencing Iohexol degradation, pH, ozone dosage, and the presence of different background ions were also evaluated. Results show that Iohexol degradation during ozonation followed the pseudo-first-order kinetics well; the degradation rate increased with the increase of pH values and reached a maximum of 1.29(±0.05)×10−1 min−1 at pH 9. As the ozone concentration gradually increased from 0.342 to 1.13 mg/L, the corresponding pseudo-first-order rate constant of Iohexol degradation increased from 7.25 (±0.30)×10−3 to 5.77(±0.26)×10−2 min−1. At pH 7, the presence of background ions have different inhibitory effects on Iohexol during ozonation degradation. Br exhibited the strongest inhibitory effect followed by HCO3− and CO32-, while Cl possessed negligible influence. Less disinfection by-products (DBPs) were formed at circumneutral pH values and low bromine concentrations (
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Kinetics and formation of disinfection byproducts during Iohexol chlor(am)ination
Separation and Purification Technology, 2020Co-Authors: Hua Shuangjing, Du Yifan, Yi-li Lin, Yuan-zhang Hou, Yan-guo Deng, Cheng-di Dong, Chiu-wen ChenAbstract:Abstract In this study, the degradation kinetics, and the formation of disinfection byproducts (DBPs) during Iohexol chlor(am)ination were studied. The chlorination kinetics can be described using a second-order model. As the pH of the solution increased, the apparent second-order rate constant of Iohexol chlorination increased considerably. The reaction rate constants of Iohexol with HOCl and OCl− were calculated as ( 3.75 ± 0.70 ) × 10 - 4 and ( 1.39 ± 1.19 ) × 10 - 4 M−1 s−1, respectively. In addition, the chloramination of Iohexol followed tertiary kinetics, and the maximum apparent rate constant of 3.78 × 10 - 6 M−1 s−1 occurred at pH 7. NH4+ can promote the degradation of Iohexol during chlorination, whereas Br− inhibits Iohexol degradation during chloramination. The formation of conventional carbonated DBPs and emerging nitrogenated DBPs during chlor(am)ination of Iohexol was measured. However, in the presence of bromide, the conversion of Iohexol to toxic iodinated DBPs increased significantly during chlorination, and chlorination resulted in higher formation of toxic I-DBP compared to chloramination. Therefore, chloramine disinfection is preferred for treating raw water containing high bromide concentrations in terms of DBP formation control.
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Investigation of Iohexol degradation kinetics by using heat-activated persulfate
Chemical Engineering Journal, 2019Co-Authors: Yuan-zhang Hou, Du Yifan, Yi-li Lin, Hua Shuangjing, Yan-guo Deng, Chiu-wen ChenAbstract:Abstract In this study, we investigated the degradation kinetics of a commonly used iodinated contrast medium, Iohexol, by using heat-activated persulfate. The results indicate that the Iohexol concentration can be effectively reduced with a removal percentage higher than 85% despite the long reaction time (2–3 h). The Iohexol disappearance fitted well with the pseudo-first-order kinetic model. The persulfate consumption almost reached the maximum value during the initial 5 min of the reaction. Subsequently, persulfate was no longer consumed, which resulted in a decrease in the reaction rate. The pseudo-first-order rate constant of Iohexol degradation significantly increased with temperature but decreased with an increase in pH from 5 to 9. The results of the quenching experiments performed using ethanol and tert-butanol indicate that the role of hydroxyl radicals was more important than that of sulfate radicals in Iohexol degradation during heat-activated persulfate oxidation. However, without heat activation, persulfate did not react with Iohexol. Therefore, the effect of pH on the HO· concentration dominated the effect of pH on Iohexol degradation. High concentrations of bicarbonate (≥5 mM), chloride (≥1 mM), and dissolved natural organic matter (≥5 mg/L) inhibited the degradation of Iohexol due to the consumption of sulfate and hydroxyl radicals. The mineralization percentage was only 3.8% (no considerable improvement) when the temperature was increased to 80 °C. The molecular structures of the intermediates contained iodine with molecular weights higher than 377 Da. Moreover, the generation of iodide was detected. The experimental results suggest that special attention should be paid to the risk of the formation of disinfection by-products in the subsequent chlorine disinfection process when treating natural water containing Iohexol through heat-activated persulfate oxidation.
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Kinetics and model development of Iohexol degradation during UV/H2O2 and UV/S2O82− oxidation
Chemosphere, 2019Co-Authors: Yuan-zhang Hou, Du Yifan, Yi-li Lin, Hua Shuangjing, Yan-guo Deng, Chiu-wen ChenAbstract:Abstract The degradation rates and kinetics of one commonly used iodinated contrast medium, Iohexol, were investigated and compared during ultraviolet (UV) photolysis, UV/H2O2 and UV/ S 2 O 8 2 − advanced oxidation processes (AOPs). Results indicate that the Iohexol degradation rate increased in the order of UV/H2O2 S 2 O 8 2 − and followed pseudo-first-order kinetics. Increasing persulfate concentration significantly increased Iohexol degradation rate, whereas increasing H2O2 concentration caused reverse effect. Radical scavenging test results show that UV photolysis, OH and radicals all contributed to Iohexol degradation during UV/ S 2 O 8 2 − , but OH was the main contributor during UV/H2O2 and was consumed by excess H2O2. The kinetic models of Iohexol degradation by both AOPs were developed, and the reaction rate constants with OH and were calculated as 5.73 (±0.02) × 108 and 3.91 (±0.01) × 1010 M−1 s−1, respectively. Iohexol degradation rate remained stable at pH 5–9 during UV irradiation and UV/H2O2, but gradually decreased at pH 5–7 and remained stable at pH 7–9 during UV/ S 2 O 8 2 − . The presence of anions displayed inhibitory effects on Iohexol degradation during UV/ S 2 O 8 2 − in the order of Cl − > HCO 3 − ≫ S O 4 2 − . UV/ S 2 O 8 2 − AOP exhibited high degradation efficiency and stability on the basis of UV irradiation, which can be applied as a promising degradation method for Iohexol. UV/ S 2 O 8 2 − AOP can effectively mineralize Iohexol to CO2 but promoted the generation of toxic iodoform (CHI3), and the subsequent chlorination had the potential to reduce the content of disinfection by-products; therefore, further evaluation of possible environmental hazards is warranted.
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Modelling of Iohexol degradation in a Fe(II)-activated persulfate system
Chemical Engineering Journal, 2019Co-Authors: Jing-ping Zhu, Yi-li Lin, Tian-yang Zhang, Tong-cheng Cao, Yang Pan, Xi-tong Zhang, Naiyun GaoAbstract:Abstract Iohexol can hardly be removed in conventional wastewater treatment processes due to its non-biodegradable and hydrophilic characteristics. In this study, a kinetic model was established to describe Iohexol degradation in Fe (II)-activated persulfate system. The developed model can well predict Iohexol degradation and evolution of sulfate radical with various initial Iohexol and oxidant (ferrous iron and persulfate) concentrations under various water matrix. The rate constant of Iohexol reacting with sulfate radical was calculated as (1.83 ± 0.10) × 109 M−1s−1. The effects of the two most common components in natural water bodies, chloride ion and natural organic matter (NOM) on Iohexol degradation, were also studied. Both experimental data and model results showed that the low concentration of chloride ion promoted Iohexol degradation while high concentration inhibited it, and NOM slightly inhibited Iohexol degradation. Besides, radical quenching tests were employed to identify the main radicals formed in the system and further verified the model accuracy. The model is also capable of predicting the atrazine degradation with the correlation coefficients between the experimental data and predicted results above 0.97, suggesting the applicability of the established model for some other recalcitrant contaminant degradation in the Fe2+/PS system.
Lars Lidgren - One of the best experts on this subject based on the ideXlab platform.
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Water uptake and release from iodine-containing bone cement
Journal of biomedical materials research. Part A, 2004Co-Authors: Fred Kjellson, Bjarne Brudeli, Ian Mccarthy, Lars LidgrenAbstract:Water uptake and release characteristics of PMMA cement containing the water-soluble contrast media Iohexol or iodixanol have been investigated. The water uptake study revealed that Iohexol had the highest uptake of water (3.7%) and that iodixanol had an uptake close to that of Palacos R (2.3% and 1.9%). The curves obtained showed the materials to follow classic diffusion theory, with an initial linearity with respect to t(1/2) making it possible to calculate the diffusion coefficients. This showed Iohexol to have the lowest diffusion coefficient, Palacos R the highest, and iodixanol close to that of Palacos R. The release study showed that more Iohexol than iodixanol was released from the bone cement; the long-term release was above 25 microg/mL for Iohexol compared to slightly above 10 microg/mL for iodixanol. A microCT investigation showed that the risk of developing an observable radiolucent zone is negligible.
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Water uptake and release from iodine-containing bone cement
Journal of Biomedical Materials Research, 2004Co-Authors: Fred Kjellson, Bjarne Brudeli, I. D. Mccarthy, Lars LidgrenAbstract:Water uptake and release characteristics of PMMA cement containing the water-soluble contrast media Iohexol or iodixanol have been investigated. The water uptake study revealed that Iohexol had the highest uptake of water (3.7%) and that iodixanol had an uptake close to that of Palacos(R) R (2.3% and 1.9%). The curves obtained showed the materials to follow classic diffusion theory, with an initial linearity with respect to t(1/2) making it possible to calculate the diffusion coefficients. This showed Iohexol to have the lowest diffusion coefficient, Palacos(R) R the highest, and iodixanol close to that of Palacos(R) R. The release study showed that more Iohexol than iodixanol was released from the bone cement; the long-term release was above 25 mug/ml, for Iohexol compared to slightly above 10 mug/mL for iodixanol. A muCT investigation showed that the risk of developing an observable radiolucent zone is negligible. (C) 2004 Wiley Periodicals, Inc
Naiyun Gao - One of the best experts on this subject based on the ideXlab platform.
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Modelling of Iohexol degradation in a Fe(II)-activated persulfate system
Chemical Engineering Journal, 2019Co-Authors: Jing-ping Zhu, Yi-li Lin, Tian-yang Zhang, Tong-cheng Cao, Yang Pan, Xi-tong Zhang, Naiyun GaoAbstract:Abstract Iohexol can hardly be removed in conventional wastewater treatment processes due to its non-biodegradable and hydrophilic characteristics. In this study, a kinetic model was established to describe Iohexol degradation in Fe (II)-activated persulfate system. The developed model can well predict Iohexol degradation and evolution of sulfate radical with various initial Iohexol and oxidant (ferrous iron and persulfate) concentrations under various water matrix. The rate constant of Iohexol reacting with sulfate radical was calculated as (1.83 ± 0.10) × 109 M−1s−1. The effects of the two most common components in natural water bodies, chloride ion and natural organic matter (NOM) on Iohexol degradation, were also studied. Both experimental data and model results showed that the low concentration of chloride ion promoted Iohexol degradation while high concentration inhibited it, and NOM slightly inhibited Iohexol degradation. Besides, radical quenching tests were employed to identify the main radicals formed in the system and further verified the model accuracy. The model is also capable of predicting the atrazine degradation with the correlation coefficients between the experimental data and predicted results above 0.97, suggesting the applicability of the established model for some other recalcitrant contaminant degradation in the Fe2+/PS system.
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degradation of Iohexol by uv chlorine process and formation of iodinated trihalomethanes during post chlorination
Chemical Engineering Journal, 2016Co-Authors: Zhen Wang, Yi-li Lin, Tian-yang Zhang, Shengji Xia, Naiyun GaoAbstract:Abstract Degradation kinetics of Iohexol by UV/chlorine advanced oxidation process (AOP) and the formation of iodinated trihalomethanes (I-THMs) during post-chlorination were investigated in this study. Iohexol, a commonly detected iodinated contrast media in water, can be effectively removed during UV/chlorine process with pseudo-first-order reaction kinetics due to the combination of UV photolysis and oxidation of hydroxyl radicals. The second-order rate constant between Iohexol and hydroxyl radicals was determined as 3.8 × 10 9 M −1 s −1 by competition kinetic experiment. Five intermediates were identified by ultra performance liquid chromatography–electrospray ionization-mass spectrometry analysis and degradation pathways of Iohexol during UV/chlorine were proposed. Effects of chlorine dose, pH and bromide concentration on Iohexol degradation and I-THM formation during post-chlorination were also studied. The results showed that Iohexol degradation was accelerated with the increase of chlorine concentration as well as the decrease of pH and bromide concentration. On the other hand, I-THM formation from post-chlorination of UV/chlorine treated Iohexol favored relatively low chlorine doses, high bromide concentrations at circumneutral conditions. Raw water experiments showed that I-THM formation after post-chlorination of UV/chlorine-treated Iohexol was lower compared to that from UV irradiation, indicating that UV/chlorine is superior to UV alone in controlling I-THM formation.
Jesse C Seegmiller - One of the best experts on this subject based on the ideXlab platform.
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verification of separate measurement procedures where analytical determinations influence the clinical interpretation of gfr Iohexol quantitation by hplc and lc ms ms
Clinical Biochemistry, 2019Co-Authors: David John Schmit, Linda J Carroll, John H Eckfeldt, Jesse C SeegmillerAbstract:Abstract Background The glomerular filtration rate (GFR) is monitored clinically to follow renal function of a patient. This is commonly performed using endogenous compounds , which estimate GFR (eGFR). However, several conditions exists which may confound or render the eGFR inaccurate. In such cases, it is appropriate to perform a procedure to directly measure GFR (mGFR). Iohexol plasma disappearance is a procedure to determine mGFR and is typically performed using bolus injection of contrast media followed by timed plasma collections. The Iohexol plasma concentrations are referenced to the dose given and the elimination rate of Iohexol is reflective of the mGFR. Therefore, analytical bias or interference in the Iohexol analytical measurement procedure will directly impact the mGFR result. Methods Plasma sample Iohexol concentrations were measured using both high performance liquid chromatography-ultraviolet detection (HPLC-UV) and liquid chromatography tandem mass spectrometry (LC-MS/MS) measurement procedures. Results were compared on 50 patients where the mGFR was calculated from the Iohexol plasma disappearance on two collection time points. Results Bland-Altman analysis illustrated LC-MS/MS to HPLC-UV. Conclusions Comparison studies of the LC-MS/MS and HPLC-UV measurement procedures displayed a mean bias of
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discordance between iothalamate and Iohexol urinary clearances
American Journal of Kidney Diseases, 2016Co-Authors: Jesse C Seegmiller, Bradley E Burns, Carrie A Schinstock, John C Lieske, Timothy S LarsonAbstract:Background Iothalamate and Iohexol are contrast agents that have supplanted inulin for the measurement of glomerular filtration rate (GFR) in clinical practice. Previous studies have noted possible differences in renal handling of these 2 agents, but clarity about the differences has been lacking. Study design Study of diagnostic test accuracy. Setting & participants 150 participants with a wide range of GFRs were studied in an outpatient clinical laboratory facility. Index tests Simultaneous urinary clearances of iothalamate, Iohexol, and creatinine. Reference test None. Outcome Relative differences between the urinary clearances. Iohexol and iothalamate in plasma and urine were assayed concurrently by a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay. Results Mean Iohexol, iothalamate, and creatinine clearances were 52±28 (SD), 60±34, and 74±40 mL/min/1.73 m(2), respectively. The proportional bias of Iohexol to iothalamate urinary clearance was 0.85 (95% CI, 0.83-0.88) and was proportional across the GFR range. The mean proportional bias of Iohexol clearance compared with creatinine clearance is 1.27 (95% CI, 1.20-1.34), whereas that of iothalamate clearance compared with creatinine clearance is 1.09 (95% CI, 1.03-1.15). Limitations Lack of reference standard. Conclusions This study reveals a significant and consistent difference between urinary clearances of iothalamate and Iohexol. Comparison of studies reporting renal clearance measurements using Iohexol versus iothalamate must account for this observed bias.
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Original Investigation Discordance Between Iothalamate and Iohexol Urinary Clearances
2016Co-Authors: Jesse C Seegmiller, Bradley E Burns, Carrie A Schinstock, John C Lieske, Timothy S LarsonAbstract:Background: Iothalamate and Iohexol are contrast agents that have supplanted inulin for the measurement of glomerular filtration rate (GFR) in clinical practice. Previous studies have noted possible differences in renal handling of these 2 agents, but clarity about the differences has been lacking. Study Design: Study of diagnostic test accuracy. Setting & Participants: 150 participants with a wide range of GFRs were studied in an outpatient clinical laboratory facility. Index Tests: Simultaneous urinary clearances of iothalamate, Iohexol, and creatinine. Reference Test: None. Outcome: Relative differences between the urinary clearances. Iohexol and iothalamate in plasma and urine were assayed concurrently by a novel liquid chromatography–tandem mass spectrometry (LC-MS/MS) assay. Results: Mean Iohexol, iothalamate, and creatinine clearances were 52 6 28 (SD), 60 6 34, and 74 6 40 mL/min/1.73 m 2 , respectively. The proportional bias of Iohexol to iothalamate urinary clearance was 0.85 (95% CI, 0.83-0.88) and was proportional across the GFR range. The mean proportional bias of Iohexol clearance compared with creatinine clearance is 1.27 (95% CI, 1.20-1.34), whereas that of iothalamate clearance compared with creatinine clearance is 1.09 (95% CI, 1.03-1.15). Limitations: Lack of reference standard. Conclusions: This study reveals a significant and consistent difference between urinary clearances of iothalamate and Iohexol. Comparison of studies reporting renal clearance measurements using Iohexol versus iothalamate must account for this observed bias. Am J Kidney Dis. 67(1):49-55. a 2016 by the National Kidney Foundation, Inc.
