Lab Values for F&E + Acid-Base

Question 1

Fluid Volume Balance
-How much does 1L of water weigh?

Answer 1

1L of water = 2.2 lbs/1 kg

Question 2

Fluid Volume Balance
-Serum osmolality

Answer 2

280-300 Osm/kg

Measures the number of osmotically active solutes in the serum.

Question 3

Fluid Volume Balance
-Hematocrit

Answer 3

42-52% males
37-48% females

Measures the percentage of whole blood that is made up of RBCs. Increased with dehydration; decreased with over-hydration

Question 4

Fluid Volume Balance
-Urea nitrogen

Answer 4

BUN 8-25 mg/dl

Produced in body as a byproduct of hepatic protein metabolism. Increased BUN reflects reduction in renal fx. Can also be affected by hydration + protein intake.

Question 5

Fluid Volume Balance
-Urine osmolality range

Answer 5

50-1400 mOsm/kg (ave 500-800)

Obtained in 24 hr urine collection. Measures solute concentration in urine. Increased w/ fluid vol. deficit, SIADH. Decreased w/ fluid vol. excess, diabetes insipidus.

Question 6

Fluid Volume Balance
-Urine specific gravity

Answer 6

physiologic range: 1.001-1.040
normal approx: 1.010–1.020

Question 7

Electrolytes
-Sodium

Answer 7

135-145 mEq/L

Most abundant cation in extracellular fluid (ECF). Only a small amt is found in ICF.

Question 8

Electrolytes
-Chloride

Answer 8

100-106 mEq/L

Most abundant extracellular anion + makes up for two-thirds of plasma anions.

Question 9

Electrolytes
-Potassium

Answer 9

3.5 – 5.0 mEq/L

Major cation in ICF.

Question 10

Electrolytes
-Calcium

Answer 10

4.3 – 5.3 mEq/L (ionized Ca++) or
8.5 – 10 mg/dL (total Ca++)
Serum value is usually total Ca++.

One of the body’s most abundant ions, primarily combined w/
phosphorus to form mineral salts of the bones + teeth.

Question 11

Electrolytes
-Phosphorus

Answer 11

1.8 – 2.6 mEq/L

Primary anion found in the intracellular fluid. Contained in the body as phosphate.

Question 12

Electrolytes
-Magnesium

Answer 12

1.5-2.0 mEq/L

Body’s second most abundant intracellular cation.

Question 13

Acid-Base Balance
-pH

Answer 13

7.35-7.45 (7.4)

Measures hydrogen ion concentration in the body fluids. Increases in H+ makes solution more acidic, decreases in H+ makes solution more alkaline.

Question 14

Acid-Base Balance
-PaCO2

Answer 14

35-45 mmHg

Partial pressure of CO2 in arterial blood. Reflection of depth of
pulmonary ventilation.

Question 15

Acid-Base Balance
-PaO2

Answer 15

80-100 mmHg

partial pressure of O2 in arterial blood. No primary role in acid-base
regulation if within normal limits.

Question 16

Acid-Base Balance
-Oxygen saturation

Answer 16

95-99%

Percentage of hemoglobin saturated by oxygen.

Question 17

Acid-Base Balance
-Base excess

Answer 17

+/-2

Amt of blood buffer that exists.

Question 18

Acid-Base Balance
-Bicarbonate

Answer 18

22-26 mEq/L

Major renal component of acid-base balance. Excreted + reproduced by the kidneys to maintain a normal acid-base. Principle buffer of
extracellular fluids in the body.