L3: PHYSICAL EXAMINATION (SPECIFIC GRAVITY)

specific gravity

• is defined as the density of a solution compared with the density of a similar volume of a distilled water at a similar temperature

1.010 (isothenuric)

• the specific gravity of plasma filtrate entering the glomerulus

hypostenuric

• below 1.010

hyperstenuric

• above 1.010

1.002 to 1.035

• normal random specimens, depending on the patient’s amount of hydration

refractometry

• determines the concentration of dissolved particles in a specimen by measuring refractive index

refractive index

• a comparison of the velocity of light in air with the velocity of light in a solution. this determines the velocity and angle at which light passes through a solution

refractometer

• make use of principle of light by using a prism to direct a specific monochromatic wavelength of daylight against a manufacturer-calibrated specific gravity scale

protein and glucose correction

• amount of protein/glucose is determined using a chemical reagent strip tests

0.003

• for each gram of protein present

0.004

• for each gram of glucose present