#Urine osmolality and specific gravity lab values

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Urine osmolality and specific gravity lab values

Urine osmolality and specific gravity lab values free#

Urine within a specified USG range was pooled (5 pools/range for dogs and 2 to 5 pools/range for cats). Graphs of the relationship between the glucose concentration and mean USG for pooled dog (A) and cat (B) urine samples with various USGs. Graphs of the relationship between the USG of unaltered pooled cat urine and the difference in USG attributable to the addition of glucose to create urine samples with glucose concentrations of 50 (A), 150 (B), 300 (C), 600 (D), 1,200 (E), and 2,400 (F) mg/dL. A relationship was considered significant at a value of P

Urine osmolality and specific gravity lab values free#

The free ions react with a pH indicator in the strip, thereby causing a change in colour, corresponding to the amount of solute present. The reagent strip in the usual urine dipstick actually measures the ionic concentration of urine. Specific gravity measured by urine dipstick Note there are potential false elevations in urine specific gravity, many of which are caused by radiographic dyes, which can produce readings >1.03, if measured at a time close to the procedure. This is a set of circumstances whereby the final urine concentration is essentially equal to that of the glomerular filtrate produced at the early proximal tubule. acute tubular necrosis) may interfere with urinary concentrating capabilities, leading to isosthenuria (a specific gravity of 1.007-1.010). Low urine specific gravity may be caused by excessive fluid intake, diabetes insipidus and diuretics, which all cause a relatively dilute urine to be formed. Therefore, for example, uncontrolled diabetes mellitus may have a high urine specific gravity (due to the high amounts of glucosuria), as well volume depletion states and proteinuric conditions. The so-called normal ranges are completely dependent on the amount of fluid ingested and solute excreted. The reference substance for comparative purposes is water, which therefore has a specific gravity of 1.000. Here are some simple facts about urine specific gravity, osmolality and their determination from the urinalysis.

#Urine osmolality and specific gravity lab values

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Urine osmolality and specific gravity lab values

1, 2 Recently, we proposed a 24-h U Osm of ⩽500 mOsm/kg as a reasonable target for urine concentration, reflecting sufficient total water intake to compensate daily losses, reduce circulating vasopressin and ensure sufficient urinary output to reduce the risk of some renal health outcomes. Specifically, urine osmolality ( U Osm) is the most precise, non-invasive biomarker available to evaluate the 24-h hydration process, as it represents the net sum of water gains, losses and neuroendocrine responses that act to maintain body water homeostasis, and responds rapidly to changes in daily water intake. Various biomarkers of urine concentration allow for individual-level daily hydration monitoring. Thus, a dietary reference value for the general population is unlikely to have much relevance for the individual. However, adequate intakes are not linked to specific health outcomes, and daily water needs are highly individual and depend upon environment, activity, diet and other factors. Adequate intakes have been established based upon population median data. Water is essential to life, represents the largest single nutrient in terms of intake, and must be replenished daily through food and fluid consumption. A receiver operating characteristic curve analysis performed on 817 urine samples demonstrates that a U SG ⩾1.013 detects U Osm>500 mOsm/kg with very high accuracy (AUC 0.984), whereas a subject-assessed U Col ⩾4 offers high sensitivity and moderate specificity (AUC 0.831) for detecting U Osm >500 m Osm/kg. In this analysis, we calculate criterion values for urine-specific gravity ( U SG) and urine color ( U Col), two measures which have broad applicability in clinical and field settings. In clinical practice and field monitoring, the measurement of U Osm is not practical. Previously, we have proposed that maintaining a 24-h urine osmolality ( U Osm) of ⩽500 mOsm/kg is a desirable target for urine concentration to ensure sufficient urinary output to reduce renal health risk and circulating vasopressin. Research focused on elucidating the factors affecting accurate assessment of hydration status appears warranted.Growing evidence suggests a distinction between water intake necessary for maintaining a euhydrated state, and water intake considered to be adequate from a perspective of long-term health. P osm, U sg, and U osm appear sensitive to incremental changes in acute hypertonic dehydration, however, the misclassified outcomes for U sg and U osm raise concerns. At the most accurate cut-off values, 1.015 and 1.020 for U sg and 700 m osm/kg and 800 m osm/kg for U osm, only 65% of the athletes were correctly classified using U sg and 63% using U osm. Using the medical decision model, sensitivity and specificity were not significant at selected cut-offs for U sg and U osm. Incremental changes in P osm were observed as subjects dehydrated by 5% of body weight and rehydrated while U sg and U osm showed delayed dehydration-related changes. This investigation: 1) compared sensitivity of urine specific gravity (U sg), urine osmolality (U osm) and a criterion measurement of hydration, plasma osmolality (P osm), at progressive stages of acute hypertonic dehydration and 2) using a medical decision model, determined whether U sg or U osm accurately reflected hydra-tion status compared to P osm among 51 subjects tested throughout the day. To reduce the adverse consequences of exertion-related and acute intentional dehydration research has focused on monitoring hydration status.

#Urine osmolality and specific gravity lab values