Creatinine in urine – a method comparison

Abstract

Drug screening in urine is widely applied in forensic toxicology. Contrary to blood analysis, excessive or reduced fluid intake can substantially alter the concentration of substances in urine. As a standard to detect urinary dilution, creatinine concentrations are analyzed. A sample with a concentration below 20 mg/dL is generally defined as too diluted to provide a valid result in abstinence control samples. This work investigates the potential of three different methods for the determination of creatinine concentrations in urine samples: A ZIC®-HILIC-based liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, a spectrophotometric method on an AU 480 chemistry system, and a portable, chemical-reaction-based, point-of-care testing device were compared by measuring 200 urine samples. When comparing the two laboratory methods, LC-MS/MS and spectrophotometry, a mean difference of 3.7 ± 14 mg/dL was found, indicating that the spectrophotometric method slightly overestimates the creatinine concentration. When comparing the LC-MS/MS method with the point-of-care testing device, a mean concentration difference within the calibration range for POCT (>20 mg/dL (excluding 16 samples) and <500 mg/dL (excluding 4 samples)) of 21 ± 37 mg/dL was found, indicating that the point-of-care testing device overestimates the measured creatinine concentration. A point-of-care testing device as used during this study can provide valuable information for on-site analysis. However, reported concentrations above 500 mg/dL should be further evaluated, for example by dilution of the sample. Copyright © 2017 John Wiley & Sons, Ltd.

Capillary electrophoresis and ultra‐high‐performance liquid chromatography methods in clinical monitoring of creatinine in human urine: A comparative study

“…The enzymatic method, routinely used in the clinical laboratory, overestimated the urinary creatinine concentrations that were 7.27% higher on average than those determined by the UHPLC-MS/MS method. The obtained results are in good agreement with the previously published results reporting lower urinary creatinine concentrations obtained with LC methods compared to colorimetric methods (Derezinski et al, 2016;Luginbühl & Weinmann, 2017). When comparing the CITP-CITP-CD method with the enzymatic one, the mean difference was −290.3 μmol L −1 .…”

“…Therefore, the separation methods represent a fast, specific, stable, and sensitive approach in bioanalysis (Moore & Sharer, 2017;Seger & Vogeser, 2012;Smith-Palmer, 2002). A high-or ultra-high-performance liquid chromatography (HPLC or UHPLC) in combination with ultraviolet (UV) or mass spectrometry (MS) has been recently used for the determination of creatinine in urine matrices (Derezinski et al, 2016;Dziadosz, 2018;Fraselle et al, 2015;Kučerová et al, 2019;Kwon, Kim, Suh, & In, 2012;Langsi, Ashu-Arrah, Ward, & Glennon, 2017;Luginbühl & Weinmann, 2017;Remane et al, 2015;Sun et al, 2019;West & Rhodes, 2014;Wijemanne, Soysa, Wijesundara, & Perera, 2018;Yen, Dahal, Lavine, Hassan, & Gamagedara, 2018;Yuan et al, 2019). In the group of electromigration techniques, capillary zone electrophoresis (CZE) with contactless conductivity detection (CD) (Grochocki, Markuszewski, & Quirino, 2017), UV detection (Huang, Chen, & Yan, 2012;Pavlíček, Tů ma, Matějčková, & Samcová, 2014;Sidorova & Grigoriev, 2012;Vitali, Goncalves, Rodrigues, Fávere, & Micke, 2017), CD/UV tandem detection (Makrlíková, Opekar, & Tů ma, 2015), or MS detection (DiBattista, Rampersaud, Lee, Kim, & Britz-McKibbin, 2017;Huang et al, 2019;Ramautar, Busnel, Deelder, & Mayboroda, 2012;Wellington et al, 2019;Wild, Shanmuganathan, Hayashi, Potter, & Briz-McKibbin, 2019;Yamamoto, Pinto-Sanchez, Bercik, & Britz-McKibbin, 2019) has been applied for creatinine.…”

Temporal Trends of Urinary Phthalate Concentrations in Two Populations: Effects of REACH Authorization after Five Years

“…The strength of the present study is certainly to have proposed a biomonitoring survey of exposure to phthalates in Italy, for a general population group. Currently, phthalate dosing studies, in Italy, are aimed to investigate specific correlations with pathologies [ 55 , 56 ], selecting samples of specific subjects, mainly children [ 55 , 56 , 57 , 58 ] and pregnant [ 59 ] or menopausal [ 60 ] women, and not to a more general exposure characterization. A second strength is to produce data, useful for the scientific debate, to confirm the temporal trends of phthalate in Europe, after the REACH application.…”

Cannabinoid concentrations in confiscated cannabis samples and in whole blood and urine after smoking CBD-rich cannabis as a “tobacco substitute”

“…the creatinine reference concentration, defined as 100 mg/dL; and CR Sample the creatinine concentration in the sample (mg/dL), measured spectrophotometrically by Jaffé's reaction on the AU480 analyzer during qualitative screening of the urine samples. Details of the creatinine determination are reported elsewhere [23].…”