urine osmolality and specific gravity lab values

approved by the Ethics Research Committee of the hospital. a significant association between urine osmolality and body mass index (BMI), creatinine clearance, as well as serum. Urine Osmolality in Treatment-naÃ¯ve HIV-positive Subjects in. Compared with the human-canine scale, the feline scale provides a closer approximation to urine osmolality of Hispaniolan Amazon parrots but still results in overestimation of osmolality. In addition, this error increases as the concentration of urine increases. Use of the reference-canine scale to approximate the osmolality of parrot urine leads to an overestimation of the true osmolality of the sample. An equation was calculated to allow specific gravity results from a medical refractometer to be converted to specific gravity values of Hispaniolan Amazon parrots: USGHAp = 0.201 +0.798(USGref). The linear relationship between refractivity measurements on a reference scale and osmolality was determined. Specific gravity and osmolality measurements were highly correlated (r = 0.96). Osmolality was measured by vapor pressure osmometry. Samples were analyzed by using a veterinary refractometer, and specific gravity was measured on both canine and feline scales. To evaluate the relationship between osmolality and specific gravity of urine samples from clinically normal adult parrots and to determine a formula to convert urine specific gravity (USG) measured on a reference scale to a more accurate USG value for an avian species, urine samples were collected opportunistically from a colony of Hispaniolan Amazon parrots (Amazona ventralis). Â© 2010 Wiley-Liss, Inc.Ĭomparison of osmolality and refractometric readings of Hispaniolan Amazon parrot (Amazona ventralis) urine.īrock, A Paige Grunkemeyer, Vanessa L Fry, Michael M Hall, James S Bartges, Joseph W In pathological urines, direct measurement of urine osmolality should be used. Pathological urines had significantly poorer correlation between USG and osmolality than 'clean' urines. For an increase in SG of 0.010, predicted osmolality increases by 182 â€‰mosm/kg/H(2) O for the reagent strip and 203 â€‰mosm/kg/H(2)O for refractometry. At a pH of 7 and with an USG of 1.010 predicted osmolality is approximately 300 â€‰mosm/kg/H(2)O for either method. The variables affecting the correlation included pH, ketones, bilirubin, urobilinogen, glucose, and protein for the reagent strip and ketones, bilirubin, and hemoglobin for the refractometry method. This study demonstrated that USG obtained by both reagent strip and refractometry had a correlation of approximately 0.75 with urine osmolality. The relationships were analyzed by linear regression. The other variables considered were pH, protein, glucose, ketones, nitrates, bilirubin, urobilinogen, hemoglobin, and leukocyte esterase. Urinalysis data on these subjects were used to determine the correlation between USG and osmolality, adjusting for other variables that may impact the relationship. Out of these, 253 USG's were measured by automated refractometry and 251 USG's were measured by reagent strip. Using our laboratory's records, we retrospectively gathered data on 504 urine specimens on patients on whom a simultaneously drawn USG and an osmolality were available. We studied the correlation of USG obtained by either method with a concurrently obtained osmolality. USG is measured either by refractometry or by reagent strip.

Urine specific gravity (USG) is often used by clinicians to estimate urine osmolality.

Imran, Sethi Eva, Goldwater Christopher, Shutty Flynn, Ethan Henner, David

Is specific gravity a good estimate of urine osmolality?

Urine osmolality and specific gravity lab values