Creatinine in urine

Representative Method Although each chemical kinetic method has its own unique considerations, the determination of creatinine in urine based on the kinetics of its reaction with picrate provides an instructive example of a typical procedure. 

Description of Method. Creatine is an organic acid found in muscle tissue that supplies energy for muscle contractions. One of its metabolic products is creatinine, which is excreted in urine. Because the concentration of creatinine in urine and serum is an important indication of renal function, rapid methods for its analysis are clinically important. In this method the rate of reaction between creatinine and picrate in an alkaline medium is used to determine the concentration of creatinine in urine. Under the conditions of the analysis, the reaction is first-order in picrate, creatinine, and hydroxide. 

This experiment includes instructions for preparing a picrate ion-selective electrode. The application of the electrode in determining the concentration of creatinine in urine (which is further described in Method 13.1) also is outlined. 

Butoxyethanol 240 mmol butoxyacetic acid/mol creatinine in urine (HGV) Post shift... 

Methylenedianiline (MDA) 50 pmol total MDA/mol creatinine in urine (BGV) Post shift for inhalation and pre-shift next day for dermal exposure... 

For humans, 80-90% of ingested nitrogen is excreted as urea. Minor contributions include ammonia and creatinine (in urine), nitrogen compounds in... 

Nitrogen compounds commonly determined are creatinine, urea, and uric acid. Creatinine is an end product of the energy process occurring within the muscles, and is thus related to muscle mass. Creatinine in urine is commonly used as an indicator and correction factor of dilution in urine. Creatinine in serum is an indicator of the filtration capacity of the kidney. Urea is the end product of the nitrogen luea cycle, starting with carbon dioxide and ammonia, and is the bulk compoimd of urine. The production of uric acid is associated with the disease gout. In some cases, it appears that the excess of uric acid is a consequence of impaired renal excretion of this substance. 

The serum creatinine concentration of a human volunteer was found to be 1.2 mg/dL. Over a 24-hour period, 1.6 L of urine was collected and the concentration of creatinine in urine was found to be 98 mg/dL. What is the creatinine clearance of the volunteer ... 

External standard procedure using ChromStar software or manual calculation using an integrator. Measure the creatinine in urine and calculate the results as mmol/mol creatinine. Measure Hb in dried blood extracts and calculate results as nmol/g Hb. 

In patients affected with GAMT deficiency, GA is elevated in urine, plasma and CSF. In addition, Cr is decreased or in the low-normal range in urine, plasma and CSF. Creatinine in urine (expressed as excretion per 24 h) and plasma is decreased. This low urinary creatinine results in increased concentration of other metabolites (e.g. amino acids, organic acids, uric acid) when expressed per mol creatinine. During treatment by Cr supplementation, GA in plasma decreases, but does not normalise. Cr in plasma and urine becomes increased. 

Amounts of total chromium were measured in lymphocytes, blood, and urine after intratracheal administration of either sodium dichromate(VI) or chromium(III) acetate hydroxide (a water-soluble chromium(III) compound) to male Wistar rats (Gao et al. 1993). The total amount of chromium administered was 0.44 mg Cr/kg body weight for each compound. The highest concentrations in tissues and urine occurred at 6 hours after treatment, the first time point examined. Mean chromium concentrations (n= 4 rats per time point) from treatment with chromium(III) were 56.3 pg/L in whole blood, 96 pg/L in plasma, 0.44 pg/1010 in lymphocytes, and 4,535.6 pg/g creatinine in urine. For treatment with chromium(VI) the levels were 233.2 pg/L for whole blood, 138 pg/L for plasma,... 

Uchida K, Gotoh A (2002) Measurement of cystatin-C and creatinine in urine. Clinica Chimica Acta 323 121-128 Umbreit A, Wiedemann G (2000) Determination of urinary protein fractions. A comparison with different electrophoretic methods and quantitatively determined protein concentrations. Clin Chim Acta 297 163-172 Viau C, Bernard A, Lauwerys R (1986) Determination of rat P2-microglobulin in urine and serum. I. Development of an immunoassay based on latex particles agglutination. J Appl Toxicol 6 185-189... 

The results of DPD/PYD measurements are usually normalized for the concentration of creatinine in urine, and presented as (nmol DPD(PYD)/mol of creatinine. This normalization will reduce the variability of results by elimination of the influence of diuresis, but the creatinine excretion itself exhibits individual biological variability of approximately 11% (R3). 

The results of measurements of urinary NTx and CTx are normalized on the concentration of creatinine in urine (U-NTx/Cr, U-CTx/Cr). The fact that the diagnostic kits for CTx measuring are produced almost only by Osteometer Biotech (Denmark), while the diagnostic sets for NTx measurement are the domain of Osteomark, Ostex Int. (USA), may help the comparability of the results of the measurements. 

Serum was either used for measuring FSH immediately or frozen until hormone determination. FSH and creatinine in urine were determined immediately. Additional urine samples were obtained to determine assay characteristics. In order to determine storage conditions, urine samples were stored at room temperature, at 4°C, at -20°C without any addition, and at — 20°C with addition of glycerol. After 1 and 4 weeks, FSH and creatinine were determined again. 

In the human female, whose pituitary hormones may be suppressed by the use of oral contraceptives, the ratio of testosterone to creatinine in urine may be used. Alternatively, a method suitable for both males and females is to measure the ratio of total testosterone to epitestosterone using gas chromatography—mass spectrometry. In this method, the bis(trimethylsilyl) derivative is formed and the intensity of the molecular ions at m/z 432, under electron impact conditions for both of the steroid derivatives, is used to determine the ratio (M. Donike and J. Zimmermann, J. Chromat, 1980, 202, 483-486). The internationally accepted limit for the ratio is currently 6. 

ACGIH TLV TWA 0.01 mg(Cd)/m3 (metal). Suspected Human Carcinogen TWA 0.002 mg(Cd)/m (respirable dust). Suspected Human Carcinogen) BEI 5 ng/g creatinine in urine 5 g/L in blood DFG MAK DFG BAT Blood 1.5 ig/dL Urine 15 g/dL. MAK Animal Carcinogen, Suspected Human Carcinogen NIOSH REL (Cadmium) Reduce to lowest feasible level... 

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