Determination of serum creatinine by isotope dilution mass spectrometry as a candidate definitive method

Welch, Michael J.; Cohen, A; Hertz, Harry S.; Ruegg, F.C.; Schaffer, Robert; Sniegoski, Lorna T.; White, Edward

doi:10.1021/ac00121a018

Cited by 81 publications

(41 citation statements)

References 24 publications

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“…Urine and serum creatinine concentrations were determined using isocratic (succinic acid-mobile phase) ion-exchange HPLC with ultraviolet detection. This method is sensitive and free from drug interference and the effect of noncreatinine chromogens in serum and provides results that range from 97 to 102% of those obtained using stable isotope mass spectrometry (37,38). Urine protein and creatinine concentrations were measured on first morning urine specimens.…”

Section: Laboratory Studiesmentioning

confidence: 99%

Clinical Trial to Evaluate Omega-3 Fatty Acids and Alternate Day Prednisone in Patients with IgA Nephropathy

Hogg¹,

Lee²,

Nardelli³

et al. 2006

Clinical Journal of the American Society of Nephrology

113

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This randomized, placebo-controlled, double-blind trial evaluated the role of prednisone and omega 3 fatty acids (O3FA) in patients with IgA nephropathy. Entry criteria were (1) biopsy-proven IgA nephropathy, (2) estimated GFR >50 ml/min per 1.73 m 2 , and (3) moderate to severe proteinuria. Thirty-three patients were randomly assigned to receive prednisone 60 mg/m 2 every other day for 3 mo, then 40 mg/m 2 every other day for 9 mo, then 30 mg/m 2 every other day for 12 mo (prednisone group); 32 were randomly assigned to receive O3FA 4 g/d for 2 yr (1.88 g eicosapentaenoic acid, 1.48 g docosahexaenoic acid; O3FA group); and 31 were randomly assigned to receive placebo (placebo group). Most (73%) patients completed 2 yr of treatment. Randomly assigned patients who were hypertensive were given enalapril 2.5 to 40 mg/d. The primary end point was time to failure, defined as estimated GFR <60% of baseline. An overall significance level of 0.10 was used. The three groups were comparable at baseline except that the O3FA group had higher urine protein to creatinine (UP/C) ratios than the placebo group (P ‫؍‬ 0.003). Neither treatment group showed benefit over the placebo group with respect to time to failure, with 14 patient failures overall (two in the prednisone group, eight in the O3FA group, and four in the placebo group). The primary factor associated with time to failure was higher baseline UP/C ratios (P ‫؍‬ 0.009). Superiority of prednisone or O3FA over placebo in slowing progression of renal disease was not demonstrated in this study. However, the relatively short follow-up period, inequality of baseline UP/C ratios, and small numbers of patients precludes definitive conclusions.

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Section: Laboratory Studiesmentioning

confidence: 99%

Clinical Trial to Evaluate Omega-3 Fatty Acids and Alternate Day Prednisone in Patients with IgA Nephropathy

Hogg¹,

Lee²,

Nardelli³

et al. 2006

Clinical Journal of the American Society of Nephrology

113

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“…The presence of clear demonstration of the traceability of the results to higher-order reference methods (10,11 ) or reference materials was the main criterion that guided our work.…”

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confidence: 99%

Reference Intervals for Serum Creatinine Concentrations: Assessment of Available Data for Global Application

et al. 2008

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BACKGROUND:Reference intervals for serum creatinine remain relevant despite the current emphasis on the use of the estimated glomerular filtration rate for assessing renal function. Many studies on creatinine reference values have been published in the last 20 years. Using criteria derived from published IFCC documents, we sought to identify universally applicable reference intervals for creatinine via a systematic review of the literature.

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“…The RSD of this method was about 2%, which is better than those in some of the GC/ MS procedures2'3, but worse than that in the report of Table 2 Analytical results by IDMS method (µg g ') of creatinine in pooled serum NIST (NBS). 4 We added known amounts of labeled creatinine and unlabeled SRM creatinine to the SRM serum and determined the amount of creatinine by IDMS method. Analytical recoveries were calculated by dividing the obtained value by the amount of unlabeled creatinine added and the expected endogenous creatinine in the SRM serum which was calculated from the measured concentration of the SRM serum (Table 1).…”

Section: Analytical Resultsmentioning

confidence: 99%

Determination of Serum Creatinine by Isotope Dilution Mass Spectrometry with Liquid Chromatographic Separation

Takatsu

Nishi

1990

ANAL. SCI.

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Isotope dilution mass spectrometry with liquid chromatography for the determination of serum creatinine is studied. After adding labeled (15N2) creatinine to the serum, creatinine was isolated using high performance liquid chromatography. Measurements were performed by electron impact mass spectrometry with use of a direct insertion device. Analytical results of the NIST (formerly NBS) SRM serum showed satisfactory agreement with the certified value; the relative standard deviation of about 2% was obtained. Measurements of creatinine concentration in serum have been performed routinely in clinical laboratories, since creatinine concentration is important in the monitoring of renal functions.To evaluate the accuracy in routine methods, both definitive methods and reference methods of known accuracy and precision are needed.Isotope dilution mass spectrometry (IDMS) has been widely accepted as a reliable analytical method and it offers a practical approach to establishing a definitive method.'In the IDMS for the serum creatinine determination, gas chromatography/ mass spectrometry (GC/ MS) has been often used.2-4 But this technique usually requires the derivatization of the compound, which usually makes the analytical procedures complicated or causes some analytical problems. To avoid these problems, liquid chromatographic separation has been attempted.5We have been developing IDMS for organic constituents in human serum and have reported IDMS for serum cholesterol and glucose using on-line and off-line LC/ MS as well as GC/ MS.6-9 In the present paper, liquid chromatography has been combined with IDMS to develop a method for the measurement of creatinine. In our method no derivatization was required and a general purpose mass spectrometer, not the specific online LC/ MS instrument, has been used. Experimental MaterialsHuman serum standard reference material (SRM 909) was obtained from National Institute of Standards and Technology (NIST; formerly National Bureau of Standards), USA. Other serum pools analyzed were frozen samples obtained from the Japan Society for Clinical Chemistry.SRM 914 creatinine with a certified purity of 99.8±0.1% was obtained from NIST. The standard solution of creatinine was prepared by dissolving the accurately weighed amount of creatinine in the weighed amount of 0.01 M hydrochloric acid.'5N2 creatinine was synthesized in our laboratory by the reaction of 15N sarcosine hydrochloride (95 atom%, ICN Biomedicals, Inc.) and 15N cyanamide (99 atom%, ICN Biomedicals, Inc.).10 The compound was purified using HPLC with the Nucleosil 5C18 column (10 mm i.d.X30 cm) and water as the mobile phase. Aqueous labeled creatinine solution was prepared by dissolving a weighed amount of labeled creatinine in a weighed amount of water. Weighed portions of the standard and the labeled creatinine solution were combined to provide a series of calibration mixtures whose unlabeled/labeled mass ratios ranged from 0.8 to 1.2.Other chemicals used were of analytical reagent grade.Sample preparation procedure A weighe...

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Determination of serum creatinine by isotope dilution mass spectrometry as a candidate definitive method

Cited by 81 publications

References 24 publications

Clinical Trial to Evaluate Omega-3 Fatty Acids and Alternate Day Prednisone in Patients with IgA Nephropathy

Clinical Trial to Evaluate Omega-3 Fatty Acids and Alternate Day Prednisone in Patients with IgA Nephropathy

Reference Intervals for Serum Creatinine Concentrations: Assessment of Available Data for Global Application

Determination of Serum Creatinine by Isotope Dilution Mass Spectrometry with Liquid Chromatographic Separation

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