LAB - Sodium, Potassium, Chloride

Question 1

What is the major extracellular cation?

Answer 1

Sodium (Na⁺)

Question 2

What percentage of extracellular cations does sodium account for?

Answer 2

90%

Question 3

Which pump maintains higher sodium concentration in extracellular fluid?

Answer 3

Na⁺-K⁺ ATPase pump

Question 4

What hormone regulates sodium reabsorption in the kidneys?

Answer 4

Aldosterone

Question 5

Where is most sodium reabsorbed in the kidneys?

Answer 5

Proximal tubules (80%)

Question 6

Which part of the kidney reabsorbs 20-25% of sodium?

Answer 6

Loop of Henle

Question 7

What is the normal reference range for sodium in serum/plasma?

Answer 7

135-145 mmol/L

Question 8

What is the normal sodium range in cerebrospinal fluid (CSF)?

Answer 8

135-150 mmol/L

Question 9

What condition is characterized by sodium levels above 145 mmol/L?

Answer 9

Hypernatremia

Question 10

What is the main cause of hypernatremia?

Answer 10

Excessive water loss

Question 11

Name a condition linked to hypernatremia due to sodium retention.

Answer 11

Conn’s syndrome (Hyperaldosteronism)

Question 12

What condition is characterized by sodium levels below 135 mmol/L?

Answer 12

Hyponatremia

Question 13

What sodium concentration is considered a medical emergency?

Answer 13

<120 mmol/L for 48 hours

Question 14

What are common causes of hyponatremia?

Answer 14

Diuretic use, renal failure, and SIADH

Question 15

Which sodium determination method is preferred for hyperlipidemic samples?

Answer 15

Direct ISE

Question 16

Which sodium method requires sample dilution?

Answer 16

Indirect ISE

Question 17

What color is observed in the colorimetric method for sodium?

Answer 17

Yellow-brown

Question 18

What reagent is used in Trinder’s colorimetric method for sodium?

Answer 18

Magnesium uranyl acetate

Question 19

What is the function of aldosterone in sodium regulation?

Answer 19

Stimulates sodium retention and potassium excretion

Question 20

What is the major intracellular cation?

Answer 20

Potassium (K⁺)

Question 21

How much more concentrated is potassium in RBCs than in plasma?

Answer 21

20 times greater

Question 22

What percentage of potassium is found in plasma?

Answer 22

2%

Question 23

Where is potassium reabsorbed in the kidneys?

Answer 23

Proximal tubules

Question 24

What process is responsible for potassium secretion in the kidneys?

Answer 24

Distal tubule secretion (regulated by aldosterone)

Question 25

What is the normal potassium range in serum?

Answer 25

3.5-5.2 mmol/L

Question 26

What is the potassium reference range in urine (24-hour collection)?

Answer 26

25-125 mmol/day

Question 27

What potassium level is considered hypokalemia?

Answer 27

<3.0 mmol/L

Question 28

What are common causes of hyperkalemia?

Answer 28

Renal failure, acidosis, and Addison’s disease

Question 29

What are common causes of hypokalemia?

Answer 29

Diuretic use, alkalosis, and insulin overdose

Question 30

What condition involves falsely elevated potassium levels?

Answer 30

Pseudohyperkalemia

Question 31

What situations can cause pseudohyperkalemia?

Answer 31

Hemolysis, thrombocytosis, prolonged tourniquet use

Question 32

Which method is the preferred choice for potassium determination?

Answer 32

ISE (Ion-Selective Electrode)

Question 33

What potassium-specific carrier is used in ISE methods?

Answer 33

Valinomycin

Question 34

Which potassium determination method uses sodium tetraphenylboron?

Answer 34

Hoffman’s colorimetric method

Question 35

What is the recommended anticoagulant for potassium analysis?

Answer 35

Heparin

Question 36

Why should whole blood not be stored on ice for potassium testing?

Answer 36

It promotes potassium release from cells

Question 37

What is the most common cause of artifactual hyperkalemia?

Answer 37

Hemolysis

Question 38

What is the major extracellular anion?

Answer 38

Chloride (Cl⁻)

Question 39

What is the normal reference range for chloride in plasma/serum?

Answer 39

98-104 mmol/L

Question 40

What is the normal chloride range in urine (24-hour collection)?

Answer 40

110-250 mmol/day

Question 41

What condition is characterized by chloride levels above 104 mmol/L?

Answer 41

Hyperchloremia

Question 42

What condition is characterized by chloride levels below 98 mmol/L?

Answer 42

Hypochloremia

Question 43

What is the most common cause of hyperchloremia?

Answer 43

Loss of bicarbonate (e.g., metabolic acidosis)

Question 44

What are common causes of hypochloremia?

Answer 44

Prolonged vomiting, diabetic ketoacidosis

Question 45

Which chloride determination method uses mercuric thiocyanate?

Answer 45

Colorimetric method

Question 46

Which chloride method forms a blue color with diphenylcarbazone?

Answer 46

Mercurimetric titration

Question 47

What reagent is used in Cotlove’s amperometric method for chloride?

Answer 47

Silver (Ag²⁺)

Question 48

What is the chloride shift?

Answer 48

The exchange of chloride ions with bicarbonate ions in red blood cells

Question 49

Which part of the kidney reabsorbs chloride passively?

Answer 49

Proximal tubules

Question 50

Where does active chloride reabsorption occur?

Answer 50

Ascending limb of the loop of Henle

Question 51

What electrolyte imbalance is commonly associated with cystic fibrosis?

Answer 51

Elevated sweat chloride levels

Question 52

What hormone conserves chloride during excessive sweating?

Answer 52

Aldosterone

Question 53

Why may marked hemolysis cause decreased chloride levels?

Answer 53

Due to the dilutional effect

Question 54

What specimen is preferred for chloride urine analysis?

Answer 54

24-hour urine collection

Question 55

What condition is associated with chloride imbalance and respiratory issues?

Answer 55

Compensated respiratory acidosis

Question 56

What condition leads to chloride loss via GI disturbances?

Answer 56

Prolonged diarrhea

Question 57

What method is most commonly used for chloride determination?

Answer 57

ISE (Ion-Selective Electrode)

Question 58

What is the primary symptom of severe hypernatremia?

Answer 58

Central nervous system (CNS) disturbances

Question 59

What is a common cause of sodium imbalance in hospitalized patients?

Answer 59

Intravenous (IV) sodium infusions

Question 60

What medical condition causes increased sodium retention?

Answer 60

Hyperaldosteronism (Conn’s syndrome)

Question 61

What condition results from decreased aldosterone levels?

Answer 61

Hypoadrenalism

Question 62

Which specimen types are suitable for sodium analysis?

Answer 62

Serum, plasma, urine, and sweat

Question 63

Why is hemolysis less likely to affect sodium levels?

Answer 63

Sodium is primarily an extracellular electrolyte.

Question 64

What is the main risk of sodium levels changing too rapidly?

Answer 64

Brain damage due to cerebral edema or osmotic demyelination

Question 65

Which condition results from increased sodium loss via the gastrointestinal tract?

Answer 65

Prolonged diarrhea

Question 66

What condition occurs when sodium levels fall below 125 mmol/L?

Answer 66

Severe neuropsychiatric symptoms

Question 67

Which hormone is released in response to low sodium levels?

Answer 67

Aldosterone

Question 68

What is the primary purpose of the sodium-potassium pump?

Answer 68

To maintain sodium outside the cell and potassium inside

Question 69

Which sodium determination method uses zinc uranyl acetate as a precipitant?

Answer 69

Suderman and Delory method

Question 70

What is the primary role of potassium in the body?

Answer 70

Regulate neuromuscular activity and heart contraction

Question 71

What is the effect of potassium imbalance on heart rhythm?

Answer 71

It can cause arrhythmias or cardiac arrest.

Question 72

What potassium level is associated with ECG changes?

Answer 72

6-7 mmol/L

Question 73

What is a common symptom of hypokalemia?

Answer 73

Muscle cramps and weakness

Question 74

Which electrolyte imbalance can be caused by excessive insulin administration?

Answer 74

Hypokalemia

Question 75

Which organ is primarily responsible for potassium excretion?

Answer 75

Kidneys

Question 76

What is the main risk of potassium levels changing too rapidly?

Answer 76

Cardiac arrest or severe muscle weakness

Question 77

What potassium reagent is commonly used in the Hoffman method?

Answer 77

Sodium tetraphenylboron

Question 78

Why should potassium samples be centrifuged immediately?

Answer 78

To prevent potassium release from cells

Question 79

Which anticoagulant is recommended for potassium analysis?

Answer 79

Heparin

Question 80

Why does storing whole blood on ice cause potassium elevation?

Answer 80

Potassium leaks from cells at low temperatures.

Question 81

What potassium-specific error occurs due to fist clenching before blood collection?

Answer 81

Pseudohyperkalemia

Question 82

How does acidosis affect potassium levels?

Answer 82

It causes potassium to shift from cells into the bloodstream.

Question 83

Which potassium imbalance is common in patients with Addison’s disease?

Answer 83

Hypokalem

Question 84

What condition results in excessive potassium loss through the gastrointestinal tract?

Answer 84

Prolonged vomiting or diarrhea

Question 85

What is the primary function of chloride in the body?

Answer 85

Maintain osmolality, blood volume, and electroneutrality

Question 86

Which organ regulates chloride through passive and active reabsorption?

Answer 86

Kidneys

Question 87

What method of chloride determination produces a reddish-brown color?

Answer 87

Mercuric thiocyanate colorimetric method

Question 88

What condition results from excessive loss of chloride via vomiting?

Answer 88

Hypochloremia