Urinalysis and Body Fluids 6th Edition by Majorie DiLorenzo, Susan Strasinger

Exercise 19

Describe the principles of the refractometer, reagent strip, and osmolality for determining specific gravity.

Step 1 of 2

Specific gravity:

Density of solution and density of same amount of distilled water are compared at same temperature.

• Specific gravity can be measured using refractometer, osmolality and reagent strip.

Refractometer to determine specific gravity:

The principle is refractive index.

Description:

• By measuring refractive index, dissolved particle concentration of a specimen can be determined.

• Refractive index is comparing light velocity in air with light velocity in solution.

• This principle is used in clinical refractometer, using prism to direct the day light wavelength against the scale for specific gravity which is calibrated.