Lab values Flashcards
Normal sodium ranges
135-145mmol/L
Sodium functions in the body
-Regulates extracellular osmotic forces (water balance & ECF volume)
-Maintains neuromuscular irritability for conduction of impulses (with K+ & Ca+)
-Regulates acid-base balance (Na+ HCO3- and Na+ phos)
-Balance mediated by aldosterone (end product of RAAS)
Na+ functions in the body + when it is low…
-When Na+ is low, renin is released and stimulates aldosterone I, ACE is released in pulmonary vessels which converts angiotensin I to II causing vasoconstriction
-Vasoconstriction increases BP and restores renal perfusion, aldosterone promotes Na+ and water reabsorption
Aldosterone + K+
Aldosterone stimulates secretion and excretion of K+
Hypernatremia + hypovolemia
->145 mmol/L
-Hypovolemic: Loss of Na+ (loop diuretics, osmotic diuresis (hyperglycemia in uncontrolled diabetes), GI losses, kidneys cannot concentrate urine
Hypernatremia + euvolemic
-Euvolomic: Loss of free water with a normal body Na+ concentration
Hypernatremia + hypervolemia
-Hypervolemic: Too much water and increased Na+ levels, over secretion of ACTH (adrenocorticoropic hormone) or aldosterone
Hypernatremia clinical manifestations
-Shrinking of brain cells, aMembrane potentials
-Weakness, lethargy, muscle twitching, hyperreflexia, confusion, coma, and seizures
-Chlorine follows Na+ (hypernatremia-hyperchloremia)
Hypernatremia ECF effects
-Hypervolemia/hypovolemia
-Neuromuscular
Hypernatremia ICF manifestations
Thirst, decreased urine output, fever and shrinkage of brain cells
Hypervolemia effects caused by hypernatremia
Increased BP, bounding pulse, venous distention, edema & weight gain
Neuromuscular effects caused by hypernatremia
-Muscle weakness
-Seizures
Hypovolemia effects caused by hypernatremia
-Weight loss, weak pulses & tachycardia
-Orthostatic hypotension
Hyperglycemia effects caused by hypernatremia
-Polyuria, polydipsia, hypovolemia, weight loss
-Late hypernatremia
Hyponatremia
-<135 mmol/L
-Hypovolemic: Loss of body fluid and Na+
-Euvolemic: Loss of Na+ without significant loss of water ie. SIADH, hypothyroidism, pneumonia, glucocorticoid deficiency)
-Hypervolemic (water intoxication): Dilutes Na+
Hypontatremia ECF & ICF effects
-Extracellular hypovolemia increases intracellular water: Edema, brain cell swelling, irritability, depression & confusion
-Extracellular hypovolemia increases systemic cellular edema, weakness, anorexia, nausea and diarrhea
Hyponatremia & water excess (ECF & ICF effects)
-ECF effects: Volume expands with hypovolemia
-ICF effect: Edema
Potassium
-3.3-5.1mmol/L
-Role in neuromuscular function
-Increased K+ stimulates insuline, aldosterone, and epinephrine secretion
-Aldosterone promotes renal secretion
-Kidneys regulate K+
-Maintained by Na+K+ active transport system which plays a role in conduction
Potassium and insulin
-K+ is required for glycogen deposition in liver and skeletal muscles
-Insulin contributes to plasma level regulation by stimulating the Na+K+ pump which moves K+ into the liver and muscles with glucose
-Intracellular movement of K+ prevents acute hyperkalemia meaning insulin can treat hyperkalemia
Facilitators of potassium out of cells
-Insuline deficiency, aldosterone deficiency, acidosis, and exercise
Hypokalemia (<3.3mmol/L) effect on body systems
-CV: Dysrhthmias: Peaked P waves, prolonged QT interval, depressed ST interval, and flattened T & U waves. Cardiac arrest, weak and irregular pulse, orthostatic hypotension
-Nervous: Lethargy, fatigue, confusion and paresthesia
-GI: N/V, decreased motility, distention, and ileum
-Kidney: Water loss, unconcentrated urine, production of ammonia and ammonium, kidney damage
-Skeletal and smooth muscle: Weakness, flaccid, paralysis, respiratory arrest, constipaton, and bladder dysfunction
Hyperkalemia (>5.1mmol/L) effect on body systems
-CV: Dysrhythmias (absent P wave, prolonged PR interval, widened QRS complex, peaked T waves), bradycardia, heart block, cardiac arrest
-Nervous: Anxiety, tingling, numbness
-GI: N/V, diarrhea, colicky pain
-Kidney: Oliguria, kidney damage
-Skeletal & smooth muscle: Initially muscles are hyperactive, later weakness and flaccid paralysis
Calcium lab values
-2.1-2.6mmol/L (total, adult)
-1.9-2.6mmol/L (total)
-1.05-1.30 mol/L (ionized, adult)
-Ionized form is most important physiologically
Calcium function
-Metabolic processes, structure of bone and teeth, enzymatic cofactor for clotting, hormone secretion and cell receptor function, plasma membrane stability and permeability, impulse transmission, contraction of muscles
Factors controlling calcium absorption and excretion
Parathyroid hormone, vitamin D, and calcitonin
Hypercalcemia (>2.6mmol/L) causes…
Hyperparathyroidism; bone metastases with Ca+ resorption from breast, prostate, renal, and cervical cancer, sarcoidosis, excess vitamin D, and tumours that procude PTH
Hypocalcemia (>2.1mmol/L) causes…
-Inadequate intestinal absorption, deposition of ionized Ca+ into bone and soft tissue, blood administration, decreases in PTH and vitamin D
Effects of hypocalcemia
Increased neuromuscular excitability
Phosphate lab values
-0.8-1.5mmol/L (adult)
-1.45-2.10mmol/L (infants and young children)
Phosphate functions
-Intracellular & extracellular anion buffer in regulation of acid-base balance, muscle contracton (as ATP)
Factors controlling phosphate absorption & excretion
Parathyroid hormone, vitamin D, and calcitonin
Hyperphosphatemia causes…
Renal failure with loss of glomerular filtration, chemotherapy that releases phosphate into serum, long-term use of laxatives or enemas containing phosphates
Effects of hyperphosphatemia
Symptoms related to low Ca+ levels; when prolonged, calcification of soft tissues in lungs, kidneys, and joints
Hypophosphatemia (<0.4mmol/L) causes
Intestinal malabsorption related to vitamin D deficiency, use of Mg and aluminum containing antacids, ETOH abuse, respiratory alkalosis, hyperparathyroidism
Effects of hypophasphatemia
Reduced O2 transport and disturbed energy metabolism, leukocyte & platelet dysfunction, deranged nerve & muscle function, irritabilty, confusion numbness, coma, convulsions, respiratory failure, cardiomyopathies, bone resorption
Magnesium lab values
-0.75-0.95mmol/L (adult)
Magnesium function
Cofactor in intracellular enzymatic reactions causing neuromuscular excitability, interacts with Ca+ and K+ and has a role in smooth muscle contraction and relaxation, absorbed in the intestine and eliminated by the kidney
Hypermagenesmia (>1.25mmol/L) causes
Renal insufficiency or failure, intake of magnesium-containing antacids, and adrenal insufficency
Hypermagenesmia effects
-Skeletal & smooth muscle contraction, excess nerve function, loss of deep tendon reflexes, N/V, hypotension, bradycardia, respiratory distress
Hypomagnesmia (<0.75mmol/L) causes
Malnutrition, malabsorption syndromes, alcoholism. urinary losses
Hypomagnesmia effects
Behavioural changes, irritability, increased reflexes, muscle cramps, ataxia, nystagmus, tetany, convulsion, tachycardia, and hypotension
Troponin T lab values
-Normal; <14 ng/L. Normal for TNT
-Borderline elevation (low level); 15-49 ng/L. Compararble to a TNT level of <0.03 ug/L
-Borderline elevation (mid-level); 50-109 ng/L. Comparable to TNT level of >0.03 ug/L> 0.10 ug/L
-Clear elevation; >109 ng/L. Comparable to a TNT level of > 0.10 ug/L
->=50 ng/L is when further assessment of symptoms
Troponin functions
-Relaxing protein that forms the troponin-tropomyosin complex for cardiac cells
-Troponin T binds troponin complex to actin and tropomyosin
-Troponin I inhibits ATPase of actomyosin
-Troponin C binding sites for Ca+ ions involved in contraction
-Troponin T and I are released during AMI
-Measured to evaluate if a AMI or other damage has occured
Troponin I
-Negative: <0.5 mcg/L
-Suspicious of injury: >0.5>2.3 mcg/L
-Positive for myocardial injury: >=2.3 mcg/L
Brain natruiretic peptide (NT-pro-BNP) functions
-Causes natriuresis
-Elevation indicates HF and may distinguish cardiac vs respiratory dyspnea
-Helps assess severity of HF
Brain natriuretic peptide (NT-pro-BNP) lab values
-Normal: 0-300 ng/L
-HF is unlikely if it is <300 ng/L
-HF is likely if: >450 ng/L for patients <50 years; >900 for patients 50-75 years; and >1800 ng/L for patients >75 years
Creatinine
-Waste product produced by protein breakdown
-Released from muscle and excreted by glomerular filtration
-As GFR declines, plasma creatinine increases
-Elevated creatinine indicates decreasing glomerular filtration
Creatinine lab values
-Normal (males): 55-106 mcmol/L
-Normal (females): 44-97 mcmol/L
-Higher values indicate severe renal disease
-Lower values indicate illnessess associated with decreased muscle mass
Blood urea nitrogen (BUN)
-Normal: 3.6-9.1 mmol/L
-Reflects glomerular filtration and urine concentrating capacity
-Because urea is filtered through the glomerulus, BUN levels increase as glomerular filtration decreases
-Increased BUN indicates dehydration and renal failure
-May increase as a result of altered protein intake and catabolsim
-Lower levels could indicate overhydration or advanced liver disease
C-reactive protein
-Inflammatory marker
-Acute phase reactant or protein synthesized in the liver
-Associated with CAD, smoking, obesity, and diabetes
-Higher risk for CAD with elevated LDL
