Exam 7: Osmometry

Question 1

Most common role for osmolality measurements

Answer 1

Screening for volatile substances (like alcohols)

Question 2

Calculated osmolality formula

Answer 2

1.86 [Na] + [Glucose] + [Urea] + 9

Question 3

Osmolal gap formula

Answer 3

Osmolal gap = measured osmolality - calculated osmolality

Question 4

Unaccounted osmolal gap formula

Answer 4

Unaccounted osmolal gap = measured osmolality - (calculated osmolality + ethanol)

Question 5

Osmolality

Answer 5

The concentration of a solution in units of weight of solute per kg of solvent (mOsm/kg)

Question 6

Clinical use of osmolality

Answer 6

Volatile ingestion (eg. alcohols)
Certain metabolic states (eg. ketoacidosis)