Urine magnesium

E494 Toffaletti, J., Abrams, B., Bird, C. and Schwing, M. (1988). Clinical validation of an automated thin-film reflectance method for measurement of magnesium in serum and urine. Magnesium 7,84-90. 

Davidson W, Barbour HM. Determination of urine magnesium using the magon method on the Monarch centrifugal analyser. Ann Clin Biochem 1990 27 595-6. 

The amount of calcium in a sample of urine was determined by a method for which magnesium is an interferent. The selectivity coefficient, Rca.Mg> for the method is 0.843. When a sample with a Mg/Ca ratio of 0.50 was carried through the procedure, an error of-3.7% was obtained. The error was +5.5% when a sample with a Mg/Ca ratio of 2.0 was used. 

If the mean urine pH of cats fed ad libitum is not below 6.4, the risk of stmvite uroHthiasis iucreases as the magnesium content of the diet iucreases. Because of very poor bioavailabiUty, iron from carbonate or oxide sources that are added to the diet should not be considered as components ia meeting the minimum nutrient level ia cats. 

Ion-selective electrodes are available for the electro analysis of most small anions, eg, haUdes, sulfide, carbonate, nitrate, etc, and cations, eg, lithium, sodium, potassium, hydrogen, magnesium, calcium, etc, but having varying degrees of selectivity. The most successful uses of these electrodes involve process monitoring, eg, for pH, where precision beyond the unstable reference electrode s abiUty to deUver is not generally required, and for clinical apphcations, eg, sodium, potassium, chloride, and carbonate in blood, urine, and semm. 

The presence of sparingly soluble components in human urine, such as calcium oxalate, calcium phosphate, magnesium ammonium phosphate, uric acid and l-cystine. Kidney stones are composed mainly of these compounds. 

Biochemical characteristics (plasma levels of alanine and aspartate transminases, alkaline phosphatase, triglycerides, cholesterol, urea, uric acid, allantoin, glucose, protein, albumin, sodium, potassium, calcium, magnesium, phosphorus urine levels of protein and glucose). 

We have found that the use of serum standards for standardizing the instrument in the laboratory is useful. However, the serum standards cannot be used for urines. In urines, one runs into other problems and needs to use aqueous standards. Therefore, at present, while atomic absorption is the instrument of choice, there is much to be desired for the determination of calcium and magnesium in the routine laboratory of clinical chemistry. 

Clinical chemistry, particularly the determination of the biologically relevant electrolytes in physiological fluids, remains the key area of ISEs application [15], as billions of routine measurements with ISEs are performed each year all over the world [16], The concentration ranges for the most important physiological ions detectable in blood fluids with polymeric ISEs are shown in Table 4.1. Sensors for pH and for ionized calcium, potassium and sodium are approved by the International Federation of Clinical Chemistry (IFCC) and implemented into commercially available clinical analyzers [17], Moreover, magnesium, lithium, and chloride ions are also widely detected by corresponding ISEs in blood liquids, urine, hemodialysis solutions, and elsewhere. Sensors for the determination of physiologically relevant polyions (heparin and protamine), dissolved carbon dioxide, phosphates, and other blood analytes, intensively studied over the years, are on their way to replace less reliable and/or awkward analytical procedures for blood analysis (see below). 

Magnesium should be replaced over 3 to 5 days because 50% of the dose is excreted in the urine. 

Several recent determinations of the alkali and alkaline earth metals in serum or urine have been reported. Barrett 29) determined potassium, sodium, and calcium in semm by diluting the samples with lanthanum chloride solution. Suttle and Field 3°) used atomic absorption spectroscopy to determine potassium and magnesium in sheep plasma. 

Savory et al. 3S) measured calcium and magnesium directly in protein-free filtrates of serum or urine. Baker et al. 36) found that both trichloroacetic acid and hydrochloric acid suppress calcium absorption and that uniform acid content is therefore required for the determination of calcium. Okuda and Sasamoto37) determined calcium by adjusting solution conditions to 20 — 50 % methanol and 650 mg % lanthanum serum is diluted 21-fold and urine is diluted 10—21 fold to bring the calcium concentration into the optimum range of 1 to 0.5 mg %. 

Osis et d. 38) have determined calcium and magnesium in urine, diet, and stool for metabolic studies, and Dennler and Drepper39) have determined calcium and magnesium in the sera of sheep and calves. 

The automated determination of magnesium in urine using o.o -dihyroxyazobenzene (DAB). The final reagent concentrations obtained are ... 

The main inorganic components of the urine are the cations Na"", C, Ca "", Mg and NH4 and the anions Cl , S04 , and HP04 , as well as traces of other ions. In total, Na"" and Cl represent about two-thirds of all the electrolytes in the final urine. Calcium and magnesium occur in the feces in even larger quantities. The amounts of the various inorganic components of the urine also depend on the composition of the diet. For example, in acidosis there can be a marked increase in the excretion of ammonia (see p. 326). Excretion of Na C, and phosphate via the kidneys is subject to hormonal regulation (see p. 330). 

These solid phases are connected to the components in Fig. 4, with which they are in reversible equilibrium. For example, if magnesium ion were added to a complex solution containing solid calcium oxalate monohydrate (COM), the magnesium would compete with calcium for an increased share of the oxalate this would reduce the amount of the calcium oxalate complex, and finally a small amount of calcium oxalate sohd would dissolve to restore the complex concentration to its equilibrium value. In urine, this picture must be extended to account for the molecular substances that coat crystals and reduce access of the solution to the surface coated crystals do not redissolve readily. 

Monitoring Maintain urine output at a level of at least 100 mL every 4 hours. Monitor serum magnesium levels and clinical status to avoid overdosage in preeclampsia. 

Drug/Lab test interactions Thiazides may decrease serum PBI levels without signs of thyroid disturbance. Thiazides also may cause diagnostic interference of serum electrolyte, blood, and urine glucose levels (usually only in patients with a predisposition to glucose intolerance), serum bilirubin levels, and serum uric acid levels. In uremic patients, serum magnesium levels may be increased. Bendroflumethiazide may interfere with the phenolsulfonphthalein test due to decreased excretion. In the phentolamine and tyramine tests, bendroflumethiazide... 

Aluminum Hydroxide + Magnesium Hydroxide (Maalox) [OTC] [Antacid/Aluminum Magnesium Salts] Uses Hyper-acidity (peptic ulcer, hiatal hernia, etc) Action Neutralizes gastric acid Dose Adults. 10-20 mL or 2-4 tabs PO qid or PRN Feds. 5-15 mL PO qid or PRN Caution [C, ] Disp Tabs, susp SE May cause t Mg in renal insuff, constipation, D Interactions In addition to AlOH, X effects OF digoxin, quinolones, phenytoin, Fe supl, ketoconazole EMS None OD May cause constipation, loss of appetite, painful urination, heart rhythm changes, muscle weakness, and peripheral edema symptomatic and supportive... 

L A. Nephrotoxicity is the most common and most serious toxicity associated with amphotericin B administration. This is manifested by azotemia (elevated serum blood urea nitrogen and creatinine), and by renal tubular acidosis, which results in the wasting of potassium and magnesium in the urine (leading to hypokalemia and hypomagnesemia, requiring oral or intravenous replacement therapy). Normochromic normocytic anemia is also seen with long-term amphotericin B administration. Elevation of hver enzymes is not associated with the use of amphotericin B. 

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