Chemistry Week 4 emma version

Indicate the area of higher concentration (extra-or intracellular fluid) and function of: Bicarbonate (HCO3)

Indicate the area of higher concentration (extra-or intracellular fluid) and function of: Bicarbonate (HCO3)

Extracellular
Electrical neutrality

List the reference range for: Sodium (Na+)

135-145 meq/L
measured by ISE

List the reference range for: Potassium (K+)

3.5-5.1 meq/L
measured by ISE (valinomycin)

List the reference range for: Chloride (Cl-)

98-107 meq/L
Measured by ISE (Ag/AgCl) or colorimetric

List the reference range for: Bicarbonate (HCO3)

23-29 meq/L
Measured by ISE, enzymatic, or colorimetric

Which hormone is responsible for water reabsorption in the kidney?

ADH (Anti-Diuretic Hormone)

Which hormone is responsible for sodium reabsorption in the kidney?

Aldosterone

Describe the iontophoresis procedure used to detect Cystic Fibrosis

Sweat test
Pilocarpine and electrical stimulation are applied to an area of the arm or leg to encourage sweating.
The sweat is then collected and then Chloride levels are measured.
People with Cystic Fibrosis have higher levels of Cl- then those that do not.
>60 mEq/L is a positive test

List the causes of Hyporatremia (Low Sodium [Causes weakness, nausea, and altered mental state])

Decreased Na intake
Decreased Aldosterone
Renal Disease (decreased NA absorption)
Diabetic Ketoacidosis
Diarrhea
Prolonged vomitting
Sweating (due to fever)

List the causes of Hypernatremia (High Sodium [Causes tremors, irritability, confusion, coma])

Increased Na intake
Decreased H20 intake
Increased Aldosterone (Causes increased Na reabsorption in kidneys [Cushings])
Diabetes Insipidus (ADH)
After insulin treatment of comatose diabetics
Burns
Excessive sweating
IV therapy (Excess saline)

What is the effect of prolonged serum-red cell contact on the concentration of Na+, K+, Cl-and HCO3- following specimen collection?

Specimen of Choice: Un-hemolyzed serum in Lithium Heparin tube
Potassium (K)- Increased. Moves out of RBC
Sodium (Na)- Decreased. Moves in to RBC
Chloride (Cl)- Decreased. Follows Sodium in to RBC
Bicarbonate (HCO3)- Decreased

How much body water is in the Extracellular compartment?

1/3

How much body water is in the Intracellular compartment?

2/3

Define: osmolality

The number of moles of solute dissolved in a solution

What causes Addison's Disease?

The body doesn't produce enough Cortisol or Aldosterone

What is the effect of Addison's Disease on Aldosterone?

Decreased

What is the effect of Addison's Disease on Sodium (Na+)?

Decreased

What is the effect of Addison's Disease on Potassium (K+)?

Increased

What causes Cushing's Disease?

The body produces too much Cortisol and Aldosterone

What is the effect of Cushing's Disease on Aldosterone?

Increased

What is the effect of Cushing's Disease on Sodium (Na+)?

Increased

What is the effect of Cushing's Disease on Potassium (K+)?

Decreased

Describe the principle of the: Osmometer (Freezing Point)

Uses the freezing point of a substance to correlate it with it's osmolality (compares it to pure water)
Decreased in proportion by the amount of solute in the body

Describe the principle of the: Osmometer (Vapor Point)

The relationship between the boiling point and vapor point of a liquid is used to measure it's osmolality (compares it to pure water)
Decreased in proportion by the amount of solute in the body

Describe the principle of the: Ion Selective Electrodes (ISE)

Uses glass electrode specific for the analyte you want to measure; connects to reference electrode at zero potential
As the substance comes in contact with glass electrode, the difference in potential is measured (potentiometry) and compared to the standard

Indicate the area of higher concentration (extra-or intracellular fluid) and function of: Sodium (Na+)

Extracellular
Transmitting nerve impulses
Maintains Osmotic pressure
Water balance
Facilitating muscle contractions
Maintains blood pressure, pH, and viscosity

Indicate the area of higher concentration (extra-or intracellular fluid) and function of: Potassium (K+)

Intracellular
Controls muscle activity

Indicate the area of higher concentration (extra-or intracellular fluid) and function of: Chloride (Cl-)

Extracellular
Osmotic pressure
pH balance
O2 and CO2 exchange in RBCs
Electrical neutrality

Which antibiotic is incorporated into the membrane of the ISE used to measure K+?

Valinomycin

Describe the Chloride Shift.

The chloride shift allows oxygen and carbon dioxide to be exchanged in RBC. When blood contains oxygen, chloride shifts from the RBCs to the plasma, and bicarbonate leaves the plasma to enter the RBC.

Describe the Reverse Chloride Shift.

When the blood contains carbon dioxide, bicarbonate exits the RBCs, and chloride shifts into the cells.

Indicate the causes of Hypokalemia. (Low potassium)

Decreased intake of Potassium
Increased Aldosterone (Increased Potassium secretion in kidneys)
Diarrhea
Vomiting
GI problems
Metabolic alkalosis
Diuretic use

Indicate the causes of Hyperkalemia. (Increased potassium)

Increased intake of Potassium
Increased RBC lysis
Anoxia/ Shock/ Circulatory Failure
Dehydration
Renal Failure
Addison's Disease (Lowered Aldosterone)
Metabolic Acidosis
Renal Tubular Acidosis

Indicate the causes of Hyperchloremia (High chloride)

Metabolic acidosis
Renal tubular acidosis
Respiratory alkalosis (Drugs, fever, anxiety)
Prolonged diarrhea
Diabetes insipidus (ADH)
Dehydration

Indicate the causes of Hypochloremia (Low chloride)

Metabolic alkalosis
Diabetic ketoacidosis
Salt losing renal disease
Vomiting
Intestinal blockage

Which of the four electrolytes routinely assayed is most affected by hemolysis?

Potassium (K+)

Describe specimen collection requirements for electrolyte analysis

Non-hemolyzed
Not exposed to air
Lithium Heparin tube
No prolonged tourniquet application

What is the purpose for measuring serum and urine osmolality?

Tracking of osmolality, homeostasis, and aldosterone
Hyperosmolar conditions: Diabetes insipidus (Decreased ADH)
Hypo-osmolar conditions: Syndrome of Inappropriate ADH (SIADH)

Give the reference ranges for Serum and Urine Osmolality

Serum: 275-295 mOsm/kg

What is the formula for calculating the Anion Gap?

[Sodium (Na) + Potassium (K)] - [Chloride (Cl) + Bicarbonate (HCO3)]

What is the formula for calculating Osmolality?

2(Na) + (Glucose/20) + (BUN/3)

What is the formula for calculating the Osmolal Gap?

Measured Osmolality - Calculating Osmolality

What is the reference range for the Anion Gap?

10-20 mmol/L

What is the reference range for the Osmolal Gap?

<10 mOsm/Kg

Cl- moves with?

Na+

Cl- moves against?

HCO3-

Sodium reference range and method of measurement

135-145 meq/L
ISE

Sodium function

Maintains osmotic pressure/H2O retention, transmits nerve impulses, muscle contractions, pH balance, and blood viscosity

Hyponatremia definition and symptoms

Low sodium
Weakness, nausea, altered mental status

Hyponatremia causes

Decreased Na intake
Diarrhea
Prolonged vomitting
Sweating (due to fever)
Diabetic ketoacidosis
Renal disease (decreased resorption of Na)
Decreased aldosterone

Hypernatremia definition and symptoms

High sodium (less common)
tremors, irritability, confusion, coma

Hypernatremia causes

Increased Na intake
Decreased H2O
Severe dehydration
After insulin treatment of comatose diabetics
Excessive sweating
Burns
Diabetes insipidus (ADH)
IV therapy (excess saline)
Increased aldosterone causes increased resorption of Na in kidneys (Cushings)

Potassium reference range and method of measurement

3.5-5.1 meq/L
ISE (valinomycin)

Potassium function

Controls muscle activity

Hypokalemia definition and symptoms

Low potassium
Muscle weakness, paralysis, breathing problems, cardia arrhythmias, death

Hypokalemia causes

Decreased K+ intake
Diarrhea
Vomiting
Increased aldosterone increases K+ secretion in kidneys
GI problems
Metabolic alkalosis
Diuretic use
Chronic starvation

Hyperkalemia definition and symptoms

High potassium
Muscle weakness, confusion, cardiac arrhythmia, cardiac arrest

Hyperkalemia causes

Increased K+ intake
Anoxia/Shock/Circulatory failure
Dehydration
Addison's disease (decreased Aldosterone)
Increased RBC lysis
Metabolic acidosis
Renal tubular acidosis
Renal failure

Chloride reference range and method of measurement

98-107 meq/L
ISE (Ag/AgCl) or colorimetric

What other test is run for Chloride?

Sweat test
Pilocarpine and electrical stimulation are applied to an area of the arm or leg to encourage sweating.
The sweat is then collected and then Chloride levels are measured.
People with Cystic Fibrosis have higher levels of Cl- then those that do not.
>60 mEq/L is a positive test

Chloride functions

Maintains electrical neutrality, osmotic pressure, pH balance, O2 and CO2 exchange in RBCs

Hypochloremia definition

Low chloride

Hypochloremia causes

Metabolic alkalosis
Diabetic ketoacidosis
Salt losing renal disease (can't resorb Cl salts properly)
Vomiting
Intestinal blockages
Decreased aldosterone (Addison's)

Hyperchloremia definition

High chloride

Hyperchloremia causes

Metabolic acidosis
Renal tubular acidosis
Respiratory alkalosis (drugs, fever, anxiety)
Prolonged diarrhea
Diabetes Insipidus (ADH)
Dehydration

Bicarb reference range and method of measurement

23-29 meq/L
ISE, or enzymatic, or colorimetric
Also measured a total CO2

Decreased HCO3 causes

Metabolic acidosis
Compensated Respiratory Alkalosis

Increased HCO3 causes

Metabolic alkalosis
Compensated Respiratory Acidosis

Na+: intra or extracellular? anion or cation?

major extracellular cation

K+: intra or extracellular? anion or cation?

major intracellular cation

Cl-: intra or extracellular? anion or cation?

main extracellular anion

HCO3: intra or extracellular? anion or cation?

extracellular anion

Bicarb calculation

90% of Total CO2

Anion Gap formula

(Na + K) - (Cl + HCO3)

Anion Gap reference range

10-20 mmol/L

Decreased anion gap causes

Instrument error
Hypoalbuminemia

Moderately increased anion gap causes

Diabetic ketoacidosis
Lactic acidosis
Ethanol
Methanol
Salicylate
Ethylene glycol

Greatly increased anion gap causes

Renal failure

Calculated osmolality formula

2(Na) + BUN/3 + Glucose/20

Osmolality reference range

275-295 mOsm/kg

Osmolal Gap formula

measured osmolality - calculated osmolality

Osmolal Gap reference range

<10 mOsm/kg

Moderately increased (6-10 over reference range) causes

Uremia
Lactic acidosis
Diabetic ketoacidosis

Large increase (over 10 mmol/L over reference range) causes

Methanol
Ethanol
Ethylene glycol
Salicylate
Renal impairment

How much of the body's water is in the extracellular component?

1/3

How much is in the intracellular compnent?

2/3

Hypotonic RBC mechanism and description

Water is transported into the cell
Solute concentration inside the cell is HIGHER
The cells inflate and eventually burst

Isotonic RBC mechanism and description

Amount of water transported into the cell is equal to the amount of water transported out from the cell
Solute concentration inside the cell is equal to the solution outside the cell

Hypertonic RBC mechanism and description

Water is transported out from the cell
Solute concentration inside the cell is LOWER
The cells shrink and become crenated

Aldosterone function

Hormone resposible for sodium reabsorption in the kidneys

Hyperaldosteronism

Cushing Disease (everything but K+ is increased)

Hypoaldosteronism

Addison's Disease (everything but K+ is decreased)

ADH function

hormone responsible for water reabsorption in the kidneys

What is the effect of prolonged serum-red cell contact on the concentration of Na+, K+, Cl-and HCO3- following specimen collection?

Na+: decreased
K+: increased
Cl-: decreased
HCO3-: decreased

Define osmolality

The number of moles of solute dissolved in a solution

Describe the principle of freezing point osmometer

Uses the freezing point of a substance to correlate it with it's osmolality (compares it to pure water)
Decreased in proportion by the amount of solute in the body
Thermister?

Describe the principle of vapor point osmometer

The relationship between the boiling point and vapor point of a liquid is used to measure it's osmolality (compares it to pure water)
Decreased in proportion by the amount of solute in the body

Describe the principle of ion selective electrodes (ISE)

Uses a glass electrode specific for the analyte being measured; connects to a reference electrode at zero potential
As the substance comes in contact with glass electrode, the difference in potential is measured (potentiometry) and compared to the standard

Describe the chloride shift and the reverse chloride shift

The chloride shift allows oxygen and carbon dioxide to be exchanged in RBC. When blood contains oxygen, chloride shifts from the RBCs to the plasma, and bicarbonate leaves the plasma to enter the RBC.

When the blood contains carbon dioxide, bicarbonate exits the RBCs, and chloride shifts into the cells.

Which of the four electrolytes routinely assayed is most affected by hemolysis?

K+