Urine specific gravity

A 2-week diary of wet and dry nights prior to intervention is useful in that it can be used to monitor the response to treatment. A first-morning urine specific gravity may help to predict response to desmopressin therapy. Polysymptomatic presentation may require a more elaborate work-up, including voiding cystourethrogram, renal and/or bladder ultrasound, urodynamics, and sleep studies. 

Lithium reduces the kidney s ability to concentrate urine and may cause a nephrogenic diabetes insipidus with low urine specific gravity and low osmolality polyuria (urine volume greater than 3 L/day). This may be treated with loop diuretics, thiazide diuretics, or triamterene. If a thiazide diuretic is used, lithium doses should be decreased by 50% and lithium and potassium levels monitored. 

Renal toxicity - Renal toxicity may be characterized by decreased creatinine clearance, cells or casts in the urine, decreased urine specific gravity, oliguria, proteinuria, or evidence of nitrogen retention. Renal damage is usually reversible. The relative nephrotoxicity of these agents is estimated to be Kanamycin = Amikacin = Gentamicin = Tobramycin Streptomycin. 

ECG, fluid and electrolyte status, urine specific gravity... 

Serum creatinine increases up to 500 mM/L after 12 months, whereas creatinine clearance decreases. Significantly increased urine volumes are accompanied by decreased urine specific gravity indicating a decreased concentrating ability. Proteinuria is significantly increased. Terminal uremia occurs after 14—15 months. 

Whole blood and urine pH and Pco2 are measured quantitatively by an electrode blood-gas system and HCO3 concentrations are calculated. Plasma and urine Na+ and K+ concentrations are measured by flame photometry and CP concentrations by electrotitration. Plasma total protein concentrations and urine specific gravity are measured by refractometry, and hematocrits are determined by a microcapillary reader. Urine osmolalities are determined by freezing-point osmometry. Plasma creatinine concentrations are determined by the Jaffe method without deproteiniza-tion. 

At 3 ppm Irritation of the eyes and upper respiratory tract, decreased body weight gain, increased urine specific gravity. 

At 1 ppm Slight irritation of the nasal mucosa and decrease in body weight in females increased urine specific gravity. 

Patients with acute severe asthma should receive supplemental oxygen therapy to maintain arterial oxygen saturation above 90% (above 95% in pregnant women and patients with heart disease). Significant dehydration should be corrected urine specific gravity may help guide therapy in young children, in whom assessment of hydration status may be difficult. 

Before initiating treatment, kidney function tests (including creatinine and urine specific gravity) and thyroid function tests electrocardiogram for patients over 50... 

A dose of 1 pg desmopressin acetate has antidiuretic activity that is equivalent to 4U arginine vasopressin. Desmopressin acetate has recently been evaluated in normal horses. The author and coworkers diluted desmopressin acetate (0.1 mg/ml) nasal spray in sterile water and administered 0.05pg/kg i.v. (25 pg, equivalent to 100 U of antidiuretic activity in a 500 kg horse) to horses with polyuria induced by repeated nasogastric intubation of water for 3 days. Urine was collected for 8h after desmopressin acetate administration and there was an increase in urine specific gravity to >1.020 from 2 to 7h after administration (Fig. 10.2). The drug had no effects on heart rate or systemic blood pressure. These preliminary data demonstrate that the i.v. administration of desmopressin acetate appears to be safe and a useful tool for the evaluation of horses with DI. 

Figure 10.2 Urine osmolality and specific gravity in six horses administered 0.05 jxg/kg desmopressin acetate (DDAVP O) or placebo ( ) i.v. at time 0. The horses had polyuria induced by repeated nasogastric intubation with water (40 ml/kg) twice daily for 3 days preceding DDAVP challenge and again 4 h after administration of DDAVP. Urine was collected for 8 h after treatment and an increase in urine specific gravity to values above >1.020 was observed from 2 to 7 h after DDAVP administration.

Urine specific gravity is useful for monitoring the response to fluid therapy. Urine specific gravity can be measured easily in the field using a... 

Urine specific gravity - increased Urine volume - decreased (oliguria)... 

Einbrodt et al. (1976) exposed students to 0.26-0.92 ppm formaldehyde vapors for 3 hours, with urine samples collected immediately after exposure and 21 hours after exposure. Urine formaldehyde and urine formic acid (formate) concentrations were found to be higher immediately after exposure compared to 21 hours later however, no baseline sample was obtained prior to exposure. If historic formaldehyde and formic acid baseline levels were assumed, then a closer examination of these data indicates that more formaldehyde (and metabolite) was excreted in the urine than could have possibly been absorbed by inhalation, indicating another route of exposure (perhaps dermal), or co-exposure to another chemical that also has formate as a metabolite (e.g., methanol), or higher personal exposures than were actually measured. There was also no indication that the urine formate levels were adjusted to compensate for urine specific gravity using urine creatinine levels, which may have markedly influenced the test results. 

Many of these tests must be performed by using sophisticated and sensitive instrumentation. However, a very simple test, the measurement of the specific gravity of urine, can be an indicator of diabetes mellitus or Bright s disease. The normal range for human urine specific gravity is 1.010-1.030. 

Urine specific gravity Vanillylmandelic acid Waxy casts... 

Glucose HDL cholesterol Phosphate Iron LDL cholesterol Lithium Magnesium Potassium Sodium Total protein Triglyceride Urea nitrogen Uric acid PCP Urine bleach Urine chromate Urine nitrates Urine pH Urine specific gravity Tliyroid (T4) Vancomycin... 

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