CHEM Electrochemistry and Electrolytes

Question 1

Sources of Error: Sodium

Answer 1

Electrolyte exclusion effect
- indirect ISE readings in samples with gross lipemia = pseudohyponatremia

Question 2

Sources of Error: Potassium

Answer 2

• Hemolysis
• Fist pumping before venipuncture
• Leukocytosis
• Thrombocytosis

Question 3

Sources of Error: Chloride

Answer 3

Lactate (grey-top)

NOTE: Chloride should be collected in lithium heparin (green-top)

Question 4

Sources of Error: Bicarbonate

Answer 4

Exposure to atmospheric air decreases [CO2] in specimen

Question 5

Sources of Error: CO2

Answer 5

Exposure to atmospheric air decreases [CO2] in specimen

Question 6

Sources of Error: Calcium

Answer 6

• Lithium heparin was not used (green-top)
• Fist pumping before venipuncture
• Hemolysis
• Icterus
• Lipemia

Question 7

Sources of Error: Phosphorus

Answer 7

• Hemolysis
• Icterus
• Lipemia
• EDTA, citrate (light blue-top), oxalate (grey-top)

NOTE: should be collected in lithium heparin (green-top)

Question 8

Sources of Error: Magnesium

Answer 8

• Hemolysis
• Icterus
• Lipemia
• EDTA, citrate (light blue-top), oxalate (grey-top)

NOTE: should be collected in lithium heparin (green-top)