CLINICAL CHEMISTRY 2

• Electrolytes are molecules capable of carrying an electric charge.
• Cations have a positive charge and are represented by the symbol ( - ).
• Anions have a negative charge and are represented by the symbol (+).
• Electrolytes are significant for volume and osmotic regulation (Na+), myocardial rhythm and contractility (K+), important cofactors in enzyme activation (Mg2+), regulation of (ATPase) ion pumps (Mg2+), neuromuscular excitability (K+), production and use of ATP from glucose (Na+), maintenance of acid-base balance (Na+), and replication of DNA and translation of mRNA.
• Other reducing agents used in the Fiske Subbarow Method include Elon (methyl amino phenol), Senidine (N - phenyl - P - Phenylene diamine hydrochloride), and Ascorbic acid.
• Xedema is a condition characterized by the accumulation of fluid in the tissues due to the retention of sodium and other electrolytes.
• The end product of the Fiske Subbarow Method is Phosphomolybdenum blue.
• Renal Tubular Defects are a type of Xedema that affects the kidneys.
• Phosphate deficiency can lead to ATP depletion.
• The Fiske Subbarow Method, also known as the Ammonium phosphomolybdate method, uses Pictol (amino naphtol sulfonic acid) as a reducing agent.
• The normal range for electrolytes is Na+ 135 - 145mmol/L, K+ 3.5 - 5.1 mmol/L, Cl - 98 - 107 mmol/L, HCO3 - 21 - 28 mEq/L or 23 - 29 mmol/L, and Mg2+ 1.26 - 2.10 mg/dL or 0.63 - 1.0 mmol/L.
• The four major electrolytes are Sodium (Na+), Potassium (K+), Chloride (Cl-), and Bicarbonate (HCO3-).
• Anion Gap is the difference between the unmeasured anions and unmeasured cations, created by the concentration difference between the commonly measured cations (Na+ & K+) and commonly measured anions (Cl- & HCO3-).
• Anion Gap is useful in indicating an increase in one or more of the unmeasured anions in the serum and acts as a form of quality control for the analyzer used to measure these electrolytes.
• Abnormal anion gaps in serum from healthy person indicates an instrument problem.
• Cations in order of greatest to least significance are Sodium, Chloride, Potassium, Bicarbonate, Calcium, Inorganic phosphate, Magnesium.
• Sodium (Na+) is also known as "Natrium" and its reference value is 135 - 145mmol/L.
• ISE (liquid-membrane) is a method used.
• Practical considerations for Magnesium include fasting required for high CHO diet to decrease levels and separate serum from cell after clotting.
• Methods for measuring Magnesium include Calmagite Method, Formazan Dye method, and Magnesium Thymol blue method.
• Hormones affecting Phosphate Concentration include PTH, Vitamin D, and Growth hormone.
• Hypermagnesemia is commonly caused by renal failure, diabetic coma, CRF/ARF, Addison's disease, and increased intake.
• AAS - reference method uses Lanthanum to remove phosphate from calcium.
• Inorganic Phosphate (PO4-) is omnipresent in its distribution, 80% in bones, 20% in soft tissues, and <1% in ECF in the form of iPO4-.
• Hypomagnesemia is frequently observed in hospitalized patients, often due to malnutrition, malabsorption, chronic alcoholism, and severe diarrhea.
• Magnesium is the 2nd most abundant cation in the body and is important in maintaining the structures of DNA, RNA, and ribosomes.
• Clark-Collip Precipitation Method results in the end product of Oxalic acid and the titrant is KMNO4.
• Ortho-Cresolpthalein Complexone Dyes (colorimetric) use Dye Arzeno III and Mg+ inhibitor is 8-hydroxyquinoline (chelator).
• Inorganic Phosphate Adult range is 2.7 - 4.5 mg/dL and Child range is 4.5 - 5.5mg/dL.
• Clinical significance of Hypophosphatemia includes Alcohol abuse, Primary hyper PTH, and Myelodysplastic syndrome.
• Ferro Ham Chloranilic Acid Precipitation Method results in the end product of Chloranilic acid.
• EDTA Titration method is a method used.
• Clinical significance of Hyperphosphatemia includes Hypo PTH, Renal failure, and Lymphoblastic leukemia.
• Potassium (K+) is also known as "Kalium", and its counterbalance/countercurrent pertains to the maintenance of balance of Na and K when coming in and out of the cell, and the balance of water in the cell.
• Hyponatremia is defined as a serum/plasma level <135mmol/L, and can be caused by increased sodium loss, increased water retention, renal failure, nephrotic syndrome, aldosterone deficiency, cancer, or syndrome of inappropriate ADH secretion (SIADH), and can result from decreased water intake.
• The ratio of potassium to sodium is 20:1.
• Hemolysis of 0.5% RBCs can increase levels by 0.5mmol/L (30% increase in gross hemolysis).
• Aldosterone promotes absorption of sodium in the distal tubule, sodium retention and K+ excretion, and this is in response to low blood volume to increase Na+ and increase H2O.
• The reference value for potassium is 3.5 - 5.1 mmol/L.
• Plasma levels of potassium are lower compared to serum levels because of the release of potassium from platelets during clot formation.