Exam 2 Flashcards
major intracellular cation and its normal value
potassium
3.5-5.0
major extracellular cation and its normal value
Sodium
136-145
major extracellular anion and its normal value
chloride
90-109
what is the endpoint of a mercurimetric chloride assay?
violet blue color-a complex of mercury and diphenylcarbozone
what 2 cations are most likely to be ordered to determine the cause of cardiac tetany?
magnesium and calcium
to what does % saturation of transferrin refer and what is the normal value?
variation of iron and TBIC
20-50%
what is hypokalemia?
low serum potassium
decreased dietary intake, vomiting, renal dysfunction
if tetany is due to calcium, what specific fraction of calcium is involved? Increased or decreased?
decreased ionized calcium
what analyte in the blood is used to measure serum phosphorus?
inorganic phosphate
what is the normal value for serum phosphorus?
2.8-4.0 mg/dl
why is it important to measure serum magnesium levels?
tetany due to magnesium deficiency
in analyzing calcium by atomic absortion, why is lanthanum added?
to prevent phosphate from interferring
calcium exists in serum as what?
ionized and protein bound
is ionized or bound protein physiologically active?
ionized calcium
a patient with lactic acid acidoisis would have a increased or decreased anion gap?
increased
what is the purpose of adding magnesium carbonate to an iron binding capacity?
removes excess unbound iron TIBC
what does TIBC measure?
estimates transferrin levels in serum
what is the fiske-subbarow method for phosphorus?
molybdate added to serum to form phosphomolybdate
what kindof relationship is between serum calcium and phosphorus?
recipricol
what is the normal serum calcium level?
8.5-10.5 mg/dl
what would be the expected test results for calcium and phosphorus in hyperparathyroidism?
increased calcium
decreased phosphorus
what is the purpose of adding stannous chloride, ferrous sulfate and ascorbic acid in the determination of inorganic phosphorus?
reducing agents
name several things that can affect the level of circulating calcium.
serum protein levels
parathyroid hormone
vitamin d
bone cell activity
what 2 hormones control serum calcium levels?
parathyroid hormone PTH- decreased
calcitonin- increased
what electrolyte is the chief plasma base that helps in maintaining osmotic pressure?
sodium Na
hemolysis has the greatest effect on what serum levels?
potassium/magnesium
what is the function of aldosterone?
increased sodium absorption
increased H2O retention
increased BP
increased blood volume
what hormone has the most control over serum phosphate levels?
PTH
what is the normal serum osmolality?
215-295 mOsm/kg of H2O
what are the 4 main buffer systems of the body?
bicarbonate carbonic acid hemoglobin buffer plasma proteins phosphoric acid
the pKa of carbonic acid is what?
6.1
what is added to the reaction mixture in calcium determinations to prevent interference by magnesium?
8-hydroxylquinoline
what component of a freezing point osmometer actually measures the sample temperature?
thermistor
what 2 properties can be used to measure osmolality?
vapor pressure and freezing point
what analytes are the main contributors to serum and urine osmolality?
electrolytes
what is the principle of the freezing point osmometer?
freezing point lowered by an amount that is directly proportional to the concentration of dissolved particles in the solution.
what does the PCO2 electrode actually measure?
pH
respiratory acidosis is an excess of?
CO2
respiratory alkalosis is and excess of?
O2
during the shift, the chloride moves from _____ to _____. what anion is exchanged for chloride?
plasma to cell
bicarbonate is exchanged for chloride
what buffer system contributes most to the regulation of blood pH?
bicarbonate/carbonic acid
what is the normal ratio of the 2 portions of the buffer system?
20:1
normal blood pH?
7.34-7.45 slightly alkaline
most of the CO2 present is in the form of what?
bicarbonate
what substance is necessary for the release of oxygen from hemoglobin?
2,3 DPG
what happens in the body to compensate for a state of metabolic acidosis?
hyperventilation
what is the cause of metabolic alkalosis?
excess of HCO3 or deficient of non carbonic acid
what is p50?
PO2 at which Hgb is 50% saturated with O2 equal to 26-27 mm Hg
lis several precautions that must be used in handliing a specimen for ABGs.
anaerobic
15 mins on ice
drawn from artery
heparinized
hyperventilation is the the common cause of what?
respiratory acidosis
what reaction is catalyzed by the enzyme carbonic anhydrase?
carbonic anhydrase breaks down to carbonic acid
CO2+H2O—> H2CO3 formation of carbonic acid from CO2+H2O
what is the normal range for pCO2?
35-45 mm hg
what is the normal range for O2?
80-100 mm hg
in general respiratory alkolosis results from what?
hypoventilation
pH=pKa + log (bicarbonate/carbonic acid)
Henderson-Hasselbalch equation
what would a shift to the right be from?
fever
what would a shift to the left be from?
increased affinity for oxygen
which anticoagulant is preferred for ABG analysis
heparin
the pO2 electrode is based on what method?
amperometric measured
what would be the breathing pattern of a patient is respiratory alkalosis?
shallow/rapid breathing
what is the compensatory mechanism in repiratory acidosis?
increasing the reabsorption of HCO3
bicarbonate in the blood due to increasing reabsorption in the kidneys
how would exposure to air bubble affect an arterial blood sample?
pO2 increase
pH increase
pCO2 decrease
hyperventilation results in the loss of what?
CO2
what events shift the oxygen dissociation curve to the left?
decreased p50, 2,3 DPG, body temp, pCO2
increased affinity of Hgb for O2, pH, CO2
supercooled solution has a lower/higher temp than its freezing point?
lower
every mole of solute decreases the freezing point of H2O by how many degrees?
1.86 C
what is the name of the rapid stirrer mechanism in an osmometer?
vibrator
what are the 4 forms of CO2 in the blood?
bicarbonate
carbonic acid
dissolved CO2
carabambino compoundds/acids
when calcium levels decline, which hormone is secreted to restore normal calcium levels?
parathyroid PTH
what gases can be measured by a co-oximeter?
carboxyhemoglobin
methemoglobin
sulfhemoglobin
how should the sample for an ABG measurement be mixed?
roll between palms
what are some suitable sites for ABG draws?
radial
brachial
femoral
temporal
value for pH
7.35-7.45
value for PO2
80-100
value for pCO2
35-45
value for O2 saturated
95-100
value for HCO3
22-26
transport of protein for copper decreased in Wilsons disease
ceuroplasma
what is oligoclonal banding?
increased CSF IgG and multiple distinct bands in globulin zone
where can oligoclonal banding be seen?
90% of MS patients
