Determination Of Serum Creatinine Research Articles

Significance of Asymptomatic Bacteriuria in Spinal Cord Injury Patients on Condom Catheter

A total of 56 male spinal cord injury patients on condom catheter drainage was studied prospectively within 6 months of the injuries for 5 years. Low bladder pressures (filling maximum 35cm. water and voiding maximum 70cm. water) were ascertained with video-urodynamics. External sphincterotomy was performed when necessary for detrusor-sphincter dyssynergia. Yearly upper tract imaging, serum creatinine levels and urine cultures were obtained. All patients had colonized urine (asymptomatic) during the entire study period. No patient sustained deterioration of the urinary tract on imaging or by serum creatinine determinations during the 5-year interval. We conclude that asymptomatic bacteriuria is of no consequence to the integrity of the upper urinary tract when low pressures are operant. (J. Urol, 143: 979–980, 1990)

Determination of creatinine in serum by high-performance liquid chromatography: A comparison of three ion-exchange methods

Three ion-exchange high-performance liquid chromatographic methods for the determination of creatinine in serum have been compared. In method 1 a strong cation exchanger was used. In method 2 a reversed-phase column was given strong cation-exchange properties by the addition of N-methyloleoyl taurate to the mobile phase. In method 3 a weak cation exchanger was used. Elution was with a pH gradient in methods 1 and 2, and isocratic elution was used in method 3. The imprecision was similar for the three methods and varied between 0.9 and 2.5% as studied within-day and between 1.4 and 3.2% from day-to-day. The lowest coefficient of variation was obtained around the upper reference limit. Analytical recoveries were quantitative for the three methods. The method with N-methyloleoyl taurate showed no advantages over the conventional strong cation exchanger. With the weak cation exchanger no interferences were detected from compounds investigated, but with the strong cation exchanger a slight interference was obtained with uric acid. We prefer the weak cation-exchange method because of its simplicity, higher throughput and absence of interference from hitherto tested compounds.

Determination of Serum and Urinary Creatinine by Reversed Phase High Performance Liquid Chromatography with Sample Direct Injection

Determination of Serum and Urinary Creatinine by Reversed Phase High Performance Liquid Chromatography with Sample Direct Injection

Ultrapure, stroma-free, polymerized bovine hemoglobin solution: Evaluation of renal toxicity

Because of recent concern about the safety of our national blood supply, there is increased interest in finding safe and effective blood substitutes. One option is the use of stroma-free hemoglobin (SFH) solutions. Recently, a SFH solution based on ultrapure, polymerized bovine hemoglobin (UPPBHg) has been shown to be effective in oxygen transport. We examined the potential renal toxicity of this material. Sprague-Dawley rats were infused with UPPBHg at doses of 25, 50, 75, and 100 ml/kg. Additional groups of rats were infused with UPPBHg at these doses with the addition of bicarbonate at a dose adequate to alkalinize the urine. Further groups of rats received UPPBHg intentionally contaminated with raw bovine blood lysate. Renal function was examined by subsequent determination of serum creatinine. UPPBHg infusion up to 50 ml/kg caused no significant change in serum creatinine; at higher doses, there was a reversible rise in creatinine at 24 hr following infusion. Addition of bicarbonate diminished the amount of reversible toxicity seen, even at doses of 100 ml/kg. In contrast, with hemolysate-contaminated UPPBHg, there were sharp increases in creatinine 24 hr after infusion of all doses tested, even at 25 ml/kg; these did not decrease significantly by 48 hr following infusion. At the higher doses tested, death occurred. These observations were not affected by simultaneous bicarbonate infusion. This study shows that UPPBHg may be administered in very large doses with only mild, reversible renal toxicity. The observation that urine alkalinization ameliorates this toxicity suggests that this may occur by hemoglobin precipitation or by a toxic effect in the renal tubules. The more severe, less reversible toxicity observed with hemolysate-contaminated solution suggests that this toxicity might be mediated by some other mechanism. These findings support UPPBHg as a potential blood substitute.

Cardiac isoenzymes and electrocardiographic changes during ritodrine tocolysis

To investigate the potential myocardial ischemic effects of ritodrine, we studied 36 singleton and four twin preterm pregnancies during ritodrine therapy. We serially determined serum creatinine phosphokinase (CPK-MB fraction) and lactic dehydrogenase isoenzymes and performed electrocardiography before and during ritodrine infusion and again within the first 24 hours of oral drug therapy. We observed that serum CPK-MB and lactic dehydrogenase isoenzymes remained within the normal range during therapy periods. The incidence of sinus tachycardia and non-specific T wave changes were 100% and 25%, respectively. In three of four twin pregnancies, ST-T segment depression in leads I, V 4, V 5, and V 6 of the electrocardiogram was noted. Our study suggests that (1) the recommended ritodrine regimen does not produce direct myocardial damage, and (2) ritodrine may cause cardiac ischemia as determined by electrocardiography, which theoretically would progress to myocardial damage if not treated properly.

A new commercial method for the enzymatic determination of creatinine in serum and urine evaluated: comparison with a kinetic Jaffé method and isotope dilution-mass spectrometry.

We evaluated a new, simple, enzymatic kinetic method from Wako Chemicals GmbH in comparison with a kinetic Jaffé method by using isotope dilution-mass spectrometry (ID-MS) as a reference method. An ID-MS-calibrated serum standard was used. Both the enzymatic and the Jaffé method correlated well with ID-MS, except for sera with high concentrations of bilirubin. Ethyl acetoacetate, acetone, and glucose in serum interfered somewhat with the Jaffé method but not with the enzymatic method. We conclude that the present enzymatic method has merit as compared with a Jaffé method for routine work, but is more expensive.

Stopped-flow determination of creatinine in human serum and food samples

The results obtained by applying a modular stopped-flow system for the determination of creatinine by the alkaline picrate method are reported. The stopped-flow technique allows the simple and rapid determination of creatinine in human serum and food samples. The calibration graph is linear in the range 1–100 μg ml−1 of creatinine and the precision is close to 3%. The method features acceptable selectivity. The initial rate is measured in only 5 s, which allows the easy application of the method to routine analyses. No pretreatment of the serum samples is required. For food samples, total creatine and creatinine have been determined in dehydrated soup and meat extract samples.

Rate of deterioration of renal function in juvenile nephronophthisis

The rate of deterioration of renal function was determined in 29 patients with juvenile nephronophthisis presenting before the age of 18.5 years. The analysis was based on 618 serial determinations of serum creatinine (SCR). By application of a new statistical method the time elapsing between different successive SCR levels was calculated. A more or less homogeneous increase of SCR was noted starting from the time when a SCR of 4 mg/dl was reached. The median time elapsing between an SCR of 2 and 4 mg/dl was 32 months, between 4 and 6 mg/dl 10 months and between 6 and 8 mg/dl 5 months. The median age at the start of renal replacement therapy or death due to uraemia, evaluated by survival analysis, was similar in both sexes.

Effect of intravenous vancomycin on renal function.

In the past, vancomycin has been reported to cause renal failure during intravenous administration; however, more recently, such renal toxicity is alleged not to occur because of increased purity of the vancomycin preparations. In this study, 23 patients were prospectively examined during intravenous vancomycin administration for changes in renal function. Vancomycin was administered for an average of 15 days. The blood urea nitrogen (BUN) changes averaged +1.7 mg/dl and the creatinine changes averaged +0.06 mg/dl. Since the accuracy of the serum creatinine determination was +/- 0.3 mg/dl, clinically significant deterioration of renal function occurred in 4 patients or 17%. Even among these 4 patients with documented worsening of renal function, we suspect that deterioration was related to the infection being treated. With close monitoring of dosing, the propensity of vancomycin to cause nephrotoxicity may be less than once thought.

Flucytosine Interference with Serum Creatinine Determinations

A patient receiving intravenous amphotericin B and oral flucytosine was found to have falsely elevated serum creatinine values. Flucytosine has been reported to interfere with serum creatinine determinations when measured by the Kodak Ektachem-700 analyzer but not when the Jaffe reaction is employed. Serum creatinine values were determined by the two methods on six serum samples obtained from this patient at various times throughout her hospitalization. Flucytosine can cause clinically significant false elevations in serum creatinine when measured by the Kodak Ektachem-700 analyzer.

Fully Enzymatic Colorimetric Assay of Serum and Urine Creatinine Which Obviates the Need for Sample Blank Measurements

Abstract A fully enzymatic method for the colorimetric determination of serum and urine creatinine is described which does not require sample blank measurements. It is based on the formation of hydrogen peroxide from creatinine in a reaction sequence catalyzed by creatinine iminohydrolase, ATP-dependent 1-methylhydantoinase, N-carbamoylsarcosine amidohydrolase and sarcosine oxidase. The hydrogen peroxide is quantitated with high sensitivity at 546 nm by a chromogenic system consisting of peroxidase, 2′-sulpho-2-methyl-benzthiazolinone hydrazone and 2,4,6-tribromo-3-hydroxy-benzoic acid. Only 20 μL of sample are needed for the assay, the total reaction being complete within 10 min at 25°. Within-run precision gave a CV of 3.1 and 1.6 % at serum creatinine concentrations of 79 and 160 μmol/L, respectively, and the standard curve is linear up to at least 1760 μmol/L. The assay yields results which agree well with those found by both an enzymatic UV-method and an alternate enzymatic colorimetric procedure necesitating sample blank measurements to correct for endogenous creatine.

Eine kinetische Methode zur direkten Bestimmung des Kreatinins im Serum mit 3,5-Dinitrobenzoesäure ohne Enteiweißung

A kinetic method is reported for the determination of creatinine in serum without deproteinization, using alkaline 3,5-dinitrobenzoate solution. The increase in absorbance at 546 nm due to the formation of an orange-red complex is measured. The relationship between the creatinine concentration and absorbance was linear up to a tested concentration of 8840 mumol/l in the aqueous standard solution. Recovery of added creatinine was 98-102%. Compared with the procedure of Jaffé, as modified by Helger et al. (Z. Klin. Chem. Klin. Biochem. 12, 344-349 (1974], the present method shows less interference by pseudo-creatinine chromogens, and no interference by high serum concentrations of bilirubin or triacylglycerols. The measured serum concentration of creatinine was not affected by cephalosporin therapy. Interferences and side reactions have been minimized or eliminated by optimization of the concentrations of all reactants and of the measurement time. The described procedure can, however, only be performed in an instrument, which permits the measurement of absorbance changes in short time intervals after the start of the reaction. In comparative studies on 212 sera, the dinitrobenzoate method and the enzymic UV-test gave similar results, whereas the Jaffé method as modified by Helger et al. gave significantly higher values.

HPLC-Methode zur simultanen Bestimmung von Harnstoff, Kreatinin und Harnsäure in Serum und Urin

A simple, rapid, and reproducible method for the determination of urea, creatinine, and uric acid in human serum and urine by ion-pair reversed-phase high-performance liquid chromatography with UV detection (196 nm) has been developed. The method involves the pretreatment of serum samples with trichloroacetic acid and centrifugation followed by the isocratic separation of compounds on a μ-Bondapak C18 column using a mobile phase consisting of 1.25 mmol/l tetrabutylammonium phosphate. For urine samples no special pretreatment is necessary. In addition, this method allows, with some limitations, the determination of creatine in serum.

The effect of tiaprofenic acid on uric acid excretion in man.

The uricosuric effect of tiaprofenic acid was evaluated in a group of normouricaemic inpatients with various rheumatic disorders. Six patients aged 26 to 60 years were maintained on a standardised low-purine diet and, after a washout period of 72 hours, tiaprofenic acid was administered in 3 oral doses of 300 mg 12-hourly. A normal renal function, as assessed by serum creatinine and creatinine clearance determinations, was considered mandatory for entry into the study. The following parameters were evaluated before and after treatment: haematological values, blood urea nitrogen (BUN), serum and urinary creatine concentrations, serum uric acid concentration and the fractional excretion rate of uric acid. Our preliminary results showed a substantial increase of urinary uric acid excretion in the samples collected after treatment, especially in the first 4 hours.

Negative interference in a kinetic Jaffé method for serum creatinine determination.

Negative interference in a kinetic Jaffé method for serum creatinine determination.

Simultaneous determination of neopterin and creatinine in serum with solid-phase extraction and on-line elution liquid chromatography.

This is a method for the simultaneous determination of neopterin, a product of interferon-gamma-activated macrophages, and creatinine in serum. Acidified, but not deproteinized serum is applied to a 4-propylbenzene sulfonic acid-modified silica sorbent cartridge, which quantitatively retains the analytes but not the serum proteins. The retained analytes are then eluted from the cartridge directly onto the liquid-chromatography column. Elution from the cartridge is facilitated by a pulse of 0.4 mol/L, pH 6.8 potassium phosphate buffer. On isocratic elution from an octadecylsilica column with potassium phosphate buffer (15 mmol/L, pH 6.0), neopterin is detected by its native fluorescence, creatinine by ultraviolet absorption. Detection limits are 0.5 nmol/L for neopterin, 1 mumol/L for creatinine at a sample volume of 100 microL. The standard curve is linear over the range of concentrations encountered in sera. For both neopterin and creatinine in serum, concentrations so measured agree well with results by established methods.

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

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

Blood Urea Nitrogen and Creatinine

The determination of serum creatinine and serum urea nitrogen levels is of great value in helping to ascertain the renal function in the clinical setting. These two serum determinations are best viewed in concert, observing their absolute levels as well as their relation to one another. The serum creatinine level is less influenced by extra-renal factors than is the serum urea nitrogen level, and is the more accurate test. Reproducibility of measurement is within 2 per cent. When the test results return, there are a number of questions to be asked: What is the normal range for the laboratory which analyzed the serum? Are the levels real; i.e., could the elevated levels be factitious? Are there extrarenal etiologies for the abnormal levels? What is the BUN to creatinine ratio? If the abnormal findings are secondary to intrinsic renal disease, what other tests will help to determine the etiology of the renal disease? The laboratory assessments of BUN levels and blood creatinine levels are "standard fare" in the assessment of renal function. They are relatively low-cost tests, are available in any standard hospital laboratory, and are relatively easy to run. They are essential in the assessment of renal function in the Emergency Department.

A peroxidase-coupled kinetic enzymatic procedure evaluated for measuring serum and urinary creatinine.

We evaluated an enzymatic procedure for the automated determination of serum and urinary creatinine. The procedure was sensitive and precise for serum creatinine concentrations as low as 3 mg/L, and the standard curve was linear to 200 mg/L. Measurements of creatinine in clinical serum and urine specimens agreed with those obtained by two other enzymatic methods and four picric acid methods. There was no interference from picrate-reactive substances tested. Among other substances, bilirubin (50-100 mg/L) interfered negatively with the assay, decreasing apparent creatinine concentrations by as much as 6 mg/L. The advantages of specificity, speed, and convenience make this enzymatic procedure an attractive primary or secondary method for creatinine determinations in clinical laboratories.

Determination of creatinine in serum with HPLC and column switching

Determination of creatinine in serum with HPLC and column switching