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

Exercise 51

After controlled fluid intake, the urine-to-serum osmolarity ratio should be at least:

A. 1:1

B. 2:1

C. 3:1

D. 4:1

Step 1 of 2

Urine osmolarity test:

• This detects the water balance of body and urine concentration.

• The normal osmolarity of urine is 500-800 mOsm (milliosmole) per kg (kilogram) of body water.

Serum osmolarity test:

It is the test to detect the amount of chemicals present in serum.

• The test is to conclude the water balance and chemicals which are dissolved in blood.

• The normal osmolarity of serum is from 275 to 300 mOsm (milliosmole) per kg (kilogram) of body water.

Urine-to-serum osmolarity:

• The ratio of urine-to-serum osmolarity gives exact evaluation at random condition the ratio is 1:1.

• After intake of fluid it reaches 3:1. If does not reaches 3:1 after fluid intake, the least ratio must be 1:1.

Therefore, ratio of urine-to-serum osmolarity after fluid intake should be at least “1:1”.Hence, the correct answer is option.