q5 - 2confused2bdoctor

[ArchivalUser]

A 45 yr. old male has routine labs drawn in clinic, the results of which are shown below:

Na+ 140 mEq/L
K+ 4.0 mEq/L
Cl- 100 mEq/L
HCO3- 26 mEq/L
Glucose 108 mg/dl
Creatinine 1.0 mg/dl
BUN 28 mg/dl

Serum osmolality in milliosmoles per kilogram H2O is equal to which of the following?
A. 280
B. 284
C. 286
D. 290
E. 296
F. 300

[ArchivalUser]

A good index of osmolarity will be two times the Na conc. (if specifically referring to B.C)

i would say the answer is....

AAA???

[ArchivalUser]

it is safe and wise to pick A but

POsm= 2 Na +GLU/18 + BUN/2.8 = 296

is it E?

[ArchivalUser]

REf Goljan RR pg 60

[ArchivalUser]

Choice (E) is the correct answer. Serum osmolality is calculated in milliosmoles per kg H2O using the following formula:

Serum osmolality = 2[Na+] + [Glucose/18] + [BUN/2.8]

Good job okt3, you rock..