is defined as density of a solution over density of water
specific gravity
Minimum SG after a standard water load should be
<1.007
SG of urine at night (Nocturia) is
<(or equal to)1.018
Px deprived of fluid for 24 hours has SG of
>1.026
Normal SG of random specimen
1.003-1.035(ave. 1.015-1.025)
TEST TO MEASURE SPECIFIC GRAVITY OF URINE
1. Direct -hydrometer/URINOMETER
2. Indirect - REFRACTOMETER
CALIBRATION SOLUTIONS FOR REFRACTOMETER
Distilled water
5% NaCl
9% Sucrose
Potassium sulfate
Distilled water SG
1.000
5% NaCl
1.022+/-0.001
9% Sucrose
1.034+/-0.001
Potassium sulfate
1.015
Consists of weighted float attached to a scale that has been calibrated in terms of urine specific gravity
- Less accurate than the other methods.
URINOMETER(Hydrometer)
URINOMETER(Hydrometer)
MAJOR DISADVANTAGE: Requires large volume of urine jQuery110108135174892977572_1499790793932
(10-15 ml)
PROPER USE OF URINOMETER
-Adequate amount of urine(......) is poured into a proper sized container
-Urinometer(.....) is added with a spinning motion
-Reading is taken at the ..... of the urine meniscus
10-15ml
weighted float
bottom
Determines the specific gravity by measuring the refractive index of a specimen
REFRACTOMETER
REFRACTOMETER-DISADVANTAGE: Corrections for ..... and ..... are still calculated
glucose, protein
REFRACTOMETER-ADVANTAGES: Requires small volume of specimen( .......drops); ..... correction solutions for refractometer