Question | Answer |
Reasons for biochemical tests | determine a disease with a metabolic basis
observe/monitor for biochemical changes that are caused by an ailment" |
Biochemical Test Purpose | Diagnosis: identifying disease
Prognosis: likely course a treatment or disease might take
Monitoring: monitor treatment for appropriateness
Screening: mandatory a specific ages, during epidemic conditions and to determine subclinical ailments |
Screening Tests | TB Test, PKU (phenylketonuria) - infants prior to hospital release, scoliosis - school children |
Serum | straw colored fluid, obtained by letting blood stand and clot (no -anticoagulants added); does not have fibrinogen |
Plasma | yellow fluid on top, anticoagulant added to blood which is centrifuged; has fibrinogen |
Serum vs. Plasma | serum does not have fibrinogen or anti-coagulants, plasma has both |
All extracted fluids must be accompanied by test order that has: | Pt. name, sex, dob, date and time of sample collection, type of test to be done, possible diagnosis, MD name/number, medications pt. is taking, if inpatient: room number, unit |
Biochemical Tests can be run for | Glucose, CBC, BUN, creatinine clearance (blood and urine), total protein, lipid panel, vit c, minerals (iron, chloride, sodium) |
Errors in Biochemical Analysis | Pre-analytical Stage, Analytical Stage, Post-Analytical Stage |
Pre-analytical Stage Errors | sample collection affected - sample contamination, inappropriate chemical in collecting apparatus, sample transport issues |
Analytical Stage Errors | errors in procedure by technicians, machine failure produces incorrect results |
Post-analytical Stage Errors | calculating, and recording results errors - report the wrong results for the wrong patient |
Interpretation of results | There is a stable range of results for different genders/age groups/ethnicities |
H2O percentages: male | 60% |
H2O percentages: female | 55% |
H2O percentages: infant | 70% |
Lean body mass H2O percentages | 75-80 |
ICF vs. ECF | 66% total body water ICF |
Water in ECF | 7-8% makes up plasma volume, rest is synovial fluid, peritoneal fluid ect. |
Water Balance | Amount of water intake should nearly equal amount of water lost |
Sources of water intake | pure water, fluids (soup, juices, milk, etc.), foods (high in H2O: fruits and vegetables) |
H2O release by oxidative metabolism | Glucose + O2 -> CO2 + H2O |
Routes of H2O Output | "Respiratory: release of H2O vapors
Skin: sensitive and insensitive perspiration
Renal: urine
GI Tract: fecal matter, stool; (sick: vomiting/diarrhea)
Eyes: tears" |
Factors that influence H2O balance | climate, disease/illness, cultural factors, availability of water or food, physical activity, medical treatment |
Osmotic Concentration | "aka osmolality
-influence H2O movement into and of cell" |
Osmotic Concentration contributing factors | "mineral concentration: K in ICF; NA, CL, HCO3, MG in ECF
other molecules: glucose, proteins (amino acids) outside of cell" |
Oncotic Pressure | the fluid pressure produced by protein levels |
Obligatory Loss | "1500mL/daily
Skin - sweat - 500mL
Lungs - gaseous H2O - 400mL
GI - fecal H2O - 100mL (enzyme & saliva - reabsorbed)
Kidney - urine - 500mL (min)" |
Reasons for water excretion | excretion of water soluble waste, to maintain proper ECF and ICF osmotic balance |
Obligatory Sources | "Oxidative metabolism - 400mL
Dietary Intake - 1100mL" |
Amount of urine is produced in 24 hours | 1500-2000 mL |
Dehydration: causes | decreased intake-rare-fasting, air travel, extreme cold temp; Increased loss - GI dist, High temp, excessive sweating, post-op, hyperventilation, diuretics(natural, medications), low BG(sweating), high BG(dilute urine produced), increased ETOH intake, DKA |
Dehydration: symptoms | Thirst, Dryness of mouth/skin - decreased skin turgor, Oliguria(400-700mL), Hypotension, Tachycardia- heart muscle, Muscle weakness, cramps, dizziness, Weight loss
Extreme - cerebral dehydration - cerebral vessels can tear - resulting in hemorrhage |
Dehydration: Management | increased oral intake, IV - 5 |
Gradual Rehydration | 2/3 of H2O balance in 1 day, important in cerebra edema; rapid cerebral rehydration can result in brain vessel rupture |
Ways by which body tries to correct dehydration | "1. Hypothalamic thirst centers stimulated- feeling of thirst-pt. drinks fluid
2. ADH production (vasopressin) is increased- diuresis prevented-less urine excreted
3. Redistribution of H2O between ICF and ECF- H2O diffuses out -isotonic balance maintain |
Electrolyte | substance whose solution conduct electricity |
Ionic substances separate into | "positive ions - cations
negative ions - anions" |
Positive Ions | Cations - potassium (K+), sodium (Na+) |
Negative Ions | Anions - Chloride (Cl-), Bicarbonate (HCO3-), Potassium Sulfate (SO4 2-), HPO4- |
ECF Ions | Sodium, chloride, Bicarbonate |
Hyponatremia: causes | More often due to excessive sodium lost the decreased intake; burns, excessive sweating, increased physical exercise, V/D, overfunction of hormonal function |
US Sodium Intake/output | Intake: 100-200mmol/L , Output: <100mmol/L |
Hyponatremia: symptoms | thirst, dryness of skin, loss of skin tone, weight loss, muscular weakness/cramping, altered cardiac function |
Hyponatremia: Treatment | "Treat underlying cause: DM, hormonal malfunctions, renal causes
Saline IV- observe while administering" |
Hypernatremia: Causes | increased sodium intake |
Hypernatremia: Symptoms | thirst (because H2O follows salt), water retention, high b/p, hypertension, dyspnea, abnormal EKG - can lead to cardiac arrest |
Potassium: Role | neuromuscular control, maintains ICF osmolality |
Hyperkalemia: Causes | protein malnutrition, vomiting, excessive sweating (excretes sodium in sweat - kidney reabsorbs sodium and excretes potassium) |
Hypokalemia: Treatment | oral supplements, IV- monitor closely, rapid absorption can cause alterations in heart function |
Hydrogen Ion Concentration | results form respiration and metabolism influence the pH of the body |
Normal pH range | 7.35-7.45 |
Buffer | combination of a weak acid and its salt or a weak base and its salt that resists the pH change |
Buffer system: H2CO3 | /HCO3- (carbonic acid/bicarbonate ion) |
Buffer system: H3PO4 | /PO4-3 (phosphoric acid/phosphate ion) |
pH scale | decides acidity/alkalinity in a system |
Acidic pH | 0 |
Neutral pH | 7 |
Alkaline pH | 14 |
Respiratory acidosis/alkalosis causes | hypo or hyperventilation |
Metabolic acidosis/alkalosis causes | dealing with oxidative products of metabolism |
Process of alkalosis/acidosis | more H+ = acidosis, more HCO3- = alkalosis
normal: hydrogen ion produced = ion excreted by lungs/kidneys, imbalance results in alkalosis or acidosis |
Body chemistry equations | CO2+ HCO3 = H2CO3 = H+ +HCO3- |
Metabolic Acidosis: Defined | increased H+ production and decreased H+ excretion |
Metabolic Acidosis: Causes - Excessive H+ | acidic food in diets, increased: ketoacidosis (DM, starvation, ETOH), lactoacidosis (exercise + dehydration), drugs (salicylates, diuretics), sulfur containing amino acids (via parenteral admin, lysine, arginine, histidine or cysteinie), diarrhea |
Metabolic Acidosis: Causes - Decreased H+ excretion | renal failure, increased sensation of pancreatic juices and enterokinal (small intestine) secretions that produce alkalinity |
Metabolic Acidosis: Management | rehydration, treat underlying cause, medications: insulin therapy for DM, chelates to remove salicylates; extreme conditions: HCO3- supplements given under careful monitoring |
Respiratory Acidosis: Defined | CO2 is being retained and it converts to H2CO3 = H+ and HCO3- |
Respiratory Acidosis: Causes | Hypoxia, anxiety, fear, trauma to brain/diaphragm, infection (pulmonary edema ie bronchitis, asthma, COPD), drug intoxication, lack of neuromuscular control |
Respiratory Acidosis: Management | air passages need to be dilated; medications: inhalers (vasodilators), antibiotic therapy; Extreme cases- ventilators (O2 support) |
Metabolic Alkalosis: Causes | removal of H+ (GI disturbances - V/D/Gastric aspirations, congenital chloride loosing diarrhea), hormonal disturbances (promote diuresis), increased intake of some drugs (over dependence on antacids) |
Metabolic Alkalosis: Management | correction of gastro disturbances; potassium therapy - monitor closely |
Respiratory Alkalosis: Defined | excess CO2 is being exhaled |
Respiratory Alkalosis: Causes | hyperventilation due to anxiety, fear, excitement; severe anemia, high altitude, excessive exercise, cerebral trauma |
Respiratory Alkalosis: Management | Breath into paper bag, rebreathe exhaled CO2 |
Hypokalemia: Symptoms | muscle aches/weakness/cramping, dizziness, generalized apathy
Extended Deficiency: EKG changes, cardiac malfunction |