CLINICAL CHEMISTRY LABORATORY

HYPERCALCEMIA (INCREASED CALCIUM)

  • Main Cause: Primary Hyperparathyroidism

  • Cancer (lung and mammary)

  • Acidosis

  • Vitamin D intoxication (increased vitamin D)

  • Multiple myeloma

  • Sarcoidosis

  • Hyperthyroidism

  • Milk-Alkali Syndrome

  • Multiple endocrine neoplasia

  • Familial Hypocalciuric hypercalcemia

  • Thyrotoxicosis

  • Hypoadrenalism

  • Iatrogenic cause

HYPOCALCEMIA (DECREASED CALCIUM)

  • Hypoparathyroidism

  • Pseudohypoparathyroidism

  • Deficiency in Vitamin D

  • Chronic Renal Failure

  • Hypomagnesemia

  • Acute pancreatitis

  • Calcitonin

  • Alkalosis

PSEUDOHYPERKALCEMIA (FALSE INCREASED CALCIUM)

  • Leukocytosis

  • Thrombocytosis

  • Hemolysis

  • Improper collection

  • Improper blood storage (blood stored in ice)

  • Certain medications (heparin and potassium-sparing diuretics)

  • Potassium contamination

  • Biologic and analytic factors

  • Prolonged tourniquet application

  • Fist clenching

  • TV fluid

  • High blast counts

CHLORIDE DETERMINATION (PRINCIPLES)

  1. SCHALES AND SCHALES

    • Hg+ Cl —> HgCl2 —> Excess Hg + diphenylcarbazone —> Violet complex

  2. Coulometric titration (Cotlove chloridometer)

    • Ag+ + Cl- —> AgCl2

  3. Schoenfeld and Lewellen

    • Cl- + Hg (SCN) —> HgCl2 + SCN- —> SCN- + Fe+++ —> Fe(SCN)3

HYPERMAGNESEMIA (INCREASED MAGNESIUM)

  • Acute/Chronic Renal Failure

  • Glomerular Filtration Rate <30 mL

  • Hypoaldosteronism

    • Increased sodium, Decreased magnesium reabsorption

  • Medications and therapy

    • Antacids (Gaviscon and Simeco)

    • Drugs that contain magnesium chloride (MgCl2)

  • Dehydration → Pseudo Hypermagnesemia

  • Bone carcinoma and Bone metastases

    • Due to increased bone loss

  • Bowel disorder

  • Hypotension

  • Bradycardia

  • Respiratory depression

  • Depressed mental state

  • Electrocardiographic abnormalities

HYPOMAGNESEMIA (DECREASED MAGNESIUM)

  • Renal

    • Tubular disorder

    • Pyelonephritis

    • Glomerulonephritis

  • Drug induced

    • Diuretics

    • Antibiotics

    • Cyclosporin

    • Digitalis and Digoxin

  • Endocrine

    • Hyperparathyroidism

    • Hyperaldosteronism

    • Hyperthyroidism

    • Hypercalcemia

    • Diabetic ketoacidosis

    • Diabetes mellitus

  • Loss of magnesium in GI tract

    • Chronic diarrhea

    • Malabsorption steatorrhea

  • Alcohol

  • Stress