Jarreau Clinical Chemistry - Elecrolyes

Question 1

Sodium is the major ________ of extracellular fluid.

Answer 1

Cation

Question 2

The major function of sodium is what?

Answer 2

Maintain osmotic pressure.

Question 3

________% of sodium is absorbed in the kidney tubules.

Answer 3

85

Question 4

Reference range of sodium.

Answer 4

135 - 145 mmol/L

Question 5

What diseases are associated with hyponatremia?

Answer 5

(1) Diabetic acidosis
(2) Diarrhea
(3) Addison’s disease
(4) Renal tubular disease

Question 6

Hypernatremia is associated with what disease states?

Answer 6

(1) Cushing’s syndrome
(2) Dehydration
(3) Hyperaldosteronism
(4) Insulin treatment of uncontrolled diabetes

Question 7

What testing method is most commonly used for sodium?

Answer 7

Ion-selective electrode.

Question 8

________ electrode is selective for sodium.

Answer 8

Glass

Question 9

Describe direct reading in electrolyte testing.

Answer 9

Sample not diluted.

Question 10

Describe indirect reading in electrolyte testing.

Answer 10

Sample diluted.

Question 11

Pseudohyponatremia is present in increased ________ or ________.

Answer 11

triglycerides; protein.

Question 12

Potassium is the major ________ of intracellular fluid.

Answer 12

cation

Question 13

Potassium reference range.

Answer 13

3.5 - 5.0 mmol/L

Question 14

Potassium is ________ times higher in cells than in plasma.

Answer 14

23

Question 15

For potassium testing, separate serum from cells to prevent what?

Answer 15

K from shifting to serum.

Question 16

Falsely increased potassium may be caused by:

Answer 16

(1) Hemolysis
(2) EDTA Contamination
(3) Prolonged tourniquet application
(4) Excessive heel or finger squeezing

Question 17

Plasma and whole blood potassium is ________ lower than serum potassium.

Answer 17

0.1 - 0.7

Question 18

Hypokalemia and hyperkalemia may cause:

Answer 18

(1) Heart arrhythmias
(2) Neuromuscular symptoms (weakness, paralysis)

Question 19

Hypokalemia can be caused by:

Answer 19

(1) Insulin injections
(2) Alkalosis
(3) GI loss
(4) Hyperaldosteronism
(5) Cushing’s syndrome

Question 20

Hyperkalemia can be caused by:

Answer 20

(1) Diabetic acidosis (metabolic)
(2) Intravascular hemolysis
(3) Severe burns
(4) Renal failure
(5) Addison’s disease

Question 21

What testing method is most commonly used for potassium?

Answer 21

Ion-selective electrode

Question 22

________ is selective for potassium.

Answer 22

Valinomycin membrane

Question 23

Chloride is the major ________ of extracellular fluid.

Answer 23

anion

Question 24

Describe the function of chloride.

Answer 24

(1) Maintains hydration
(2) Osmotic pressure regulation
(3) Normal anion-cation balance

Question 25

Chloride reference range.

Answer 25

98-106 mmol/L

Question 26

Chloride generally follows ________ so increase and decrease in same conditions.

Answer 26

Sodium

Question 27

Hypochloremia is caused by:

Answer 27

(1) Diabetic acidosis (excessive acid production) (2) Chronic pyelonephritis (3) Prolonged vomiting (4) Aldosterone deficiency

Question 28

Hyperchloremia is caused by:

Answer 28

(1) Prolonged diarrhea (excessive bicarbonate loss) (2) Renal tubular acidosis (3) Adrenocortical hyperfunction

Question 29

What is the most common method for chloride testing?

Answer 29

Ion-selective electrode.

Question 30

What type of electrode is used for chloride testing?

Answer 30

AgCl (silver chloride) reference electrode.

Question 31

Describe coulometric titration for chloride testing.

Answer 31

Generation of Ag ions which combine with Cl ions.

Question 32

Describe colorimetry using Hg(SCN)2 for chloride testing.

Answer 32

Automated thiocyanate method. Forms reddish color with peak at 480 nm.

Question 33

Sweat chloride is elevated in what disease state?

Answer 33

Cystic fibrosis.

Question 34

What is the testing method used in sweat chloride testing?

Answer 34

Iontophoresis

Question 35

In sweat chloride testing, what drug is used to induce sweating?

Answer 35

Pilocarpine

Question 36

In sweat chloride testing, what chloride result would be indicative of cystic fibrosis?

Answer 36

>60 mmol/L

Question 37

Describe the function of the chloride shift.

Answer 37

A buffering system of the blood (acid-base balance).

Question 38

In chloride shift, ________ pulled out of erythrocytes and ________ moves into erythrocytes, resulting in decreased serum ________.

Answer 38

bicarbonate; chloride; chloride

Question 39

Reference range of potassium.

Answer 39

3.5 - 5.0 mmol/L

Question 40

Potassium is ________ times higher in cells than in plasma.

Answer 40

23

Question 41

How should samples collected for potassium testing be handled?

Answer 41

Separate from cells quickly to prevent K from shifting to serum.

Question 42

Total CO2 is calculated by the addition of what three analyses?

Answer 42

Carbon dioxide, bicarbonate, carbonic acid.

Question 43

CO2 generally reflects what other analytes concentration?

Answer 43

Bicarbonate

Question 44

What three testing methods are used in CO2 testing?

Answer 44

(1) Volumetric (2) Manometric (3) Colorimetric

Question 45

The anion gap is a calculation that reflects differences between:

Answer 45

Unmeasured cations and anions.

Question 46

Anion gap can be used as ________ for measuring all electrolytes.

Answer 46

analytical QC

Question 47

If there is an abnormal anion gap for multiple patients, what should the technologist suspect?

Answer 47

Problems with electrolyte measurements.

Question 48

List the three unmeasured cations.

Answer 48

(1) Potassium (2) Calcium (3) Magnesium

Question 49

List the three unmeasured anions.

Answer 49

(1) Albumin (2) Sulfate (3) Phosphate

Question 50

What is the calculation of anion gap? (with K)

Answer 50

[(Na)+(K)] - [(Cl)+(HCO3)]

Question 51

What is the calculation of anion gap? (without K)

Answer 51

(Na) - [(Cl)+(HCO3)]

Question 52

What is the reference range for the anion gap if you include potassium in the calculation?

Answer 52

10-20 mmol/L

Question 56

What is the reference range for the anion gap if you do not include potassium in the calculation?

Answer 56

7 - 16 mmol/L

Question 57

For an increased anion gap, what would cause an increased concentration of unmeasured anions?

Answer 57

(1) Alcohols & Salicylates (2) Ketones (3) Lactic Acid

Question 58

For an increased anion gap, what would cause an increased concentration of unmeasured cations?

Answer 58

(1) Low serum Magnesium (2) Low serum Calcium

Question 59

For a decreased anion gap, what would cause a decrease concentration of unmeasured anions?

Answer 59

Albumin loss.

Question 60

For a decreased anion gap, what would cause an increase concentration of unmeasured cations?

Answer 60

(1) High serum Magnesium (2) High serum Calcium (3) Lithium therapy

Question 61

Conditions causing an increased unmeasured anions.

Answer 61

S alicylate Intoxication L actic Acidosis U measured ions M ethanol P olyethylene Glycol E thanol D iabetic Ketoacidosis

Question 62

Define osmolality.

Answer 62

Measure of total concentration (number) of dissolved particles in a solution (molecular weight, size, density, or type of particle does not matter).

Question 63

Osmolality can be measured directly - describe the two practical testing methods.

Answer 63

(1) Freezing point depression (2) Vapor pressure depression

Question 64

Define the equation to calculate osmolality.

Answer 64

2Na + (Glucose/18) + (BUN/2.8)

Question 65

When measured osmolality is >10 higher than calculated osmolality, this indicates what?

Answer 65

Presence of exogenous unmeasured anions (e.g., methanol, ethanol, ketone bodies)

Question 66

Urine osmolality is best used to evaluate what disease state?

Answer 66

Renal tubular function

Question 67

Urine to serum osmolality ratio is best used to determine…

Answer 67

The kidney concentrates to glomerular filter.

Question 68

What is the function of magnesium?

Answer 68

Calcium channel blocking agent (affects heart).

Question 69

Magnesium is elevated in what disease state?

Answer 69

Renal failure.

Question 70

Magnesium is decreased in what disease state?

Answer 70

(1) Cardiac disorders (2) Diabetes mellitus (3) Diuretics, alcohol or other drugs (4) Tetany

Question 71

List the testing methodologies used for magnesium testing.

Answer 71

(1) Atomic absorption (2) Colorimetric methods

Question 72

In cases of Tetany, suspect…

Answer 72

Decreased calcium FIRST, then decreased magnesium or potassium.

Question 73

What is the function of calcium?

Answer 73

Combines with phosphate in bone and teeth.

Question 74

Calcium plasma distribution: ________ protein bound, ________ ionized (active), and ________ complexed.

Answer 74

45%; 45%; 10%

Question 75

What are the three hormones that control calcium.

Answer 75

(1) PTH (2) Calcitonin (3) Vitamin D

Question 76

PTH (increases/decreases) calcium.

Answer 76

Increases.

Question 77

Calcitonin (increases/decreases) calcium by:

Answer 77

Decreases; inhibits bone reabsorption.

Question 78

Vitamin D (increases/decreases) calcium by:

Answer 78

Increases; increases absorption in the intestines.

Question 79

What are the symptoms of hypercalemia.

Answer 79

Muscle weakness and disorientation.

Question 80

What conditions may cause hypercalcemia?

Answer 80

(1) Hyperparathyroidism (2) cancer with bone metastasis (3) Multiple myeloma (4) Renal failure

Question 81

What conditions may cause hypocalcemia?

Answer 81

(1) Hypoparathyroidism (2) Decreased serum albumin (3) Decreased vitamin D

Question 82

What are the testing methodologies for calcium?

Answer 82

(1) Atomic absorption spectroscopy - reference method (2) Colorimetric method - most common