Exam II Acid/Base Balance, Electrolytes, Osmometer Flashcards
Major intracellular cation
Normal value
Potassium
3.5-5.0 mM/L
Major extracellular cation
Normal Value
Sodium
136-145 mM/L
Major extracellular anion
Normal Value
Chloride
90-109 mM/L
What is the endpoint of mercurimetric chloride assay?
when excess Hg2+ forms a complex with an indicator like dyphenylcarbazon, producing a violet-blue color
What two cations are most likely to be ordered to determine the cause of cardiac tetany?
calcium
magnesium
calculate anion gap. be able to correlate abnormal anion gaps with other test results (such as BUN) or with instrument/tech errors
(Na + K)-(Cl + HCO3) = 12-20mmol/L
Na - (Cl + HCO3) = 8-18 mmol/L
What does %saturation refer to?
Normal value?
%saturation= serumFe/TIBC x 100
20-50%
What is hypokalemia?
low serum potassium
caused by dietary intake
If tetany is due to calcium, what specific fraction of calcium is involved?
Will it be increased or decreased?
Ionized(free) calcium
decreased
What analyte in the blood is used to measure serum phosphorous?
What is the normal value of serum phosphorous?
inorganic phosphorous
2.7-4.5 mg%
Why is it important to measure serum magnesium levels?
check for tetany due to magnesium deficiency
In analyzing calcium by atomic absorption, why is lanthanum added?
to prevent interference of phosphate
Calcium exist in serum as?
Which is physiologically active?
ionized(free) and protein bound
free
A patient with lactic acid acidosis would have an (increased/decreased) anion gap?
increased
What is the purpose of adding magnesium carbonate to an iron binding capacity?
to remove excess unbound iron
What does TIBC measure?
estimates transferrin level in serum
In what method is phosphate in serum combined with ammonium molybdate to form phosphomolybdate, which is then reduced to aminonapthosulfonic acid which is measured with spectrophotometery?
Fiske-Subbarow method for Phosphorus
Serum calcium and phosphorous have what kind of relationship?
reciprocal
What is the normal serum calcium level?
8.4-10.2 mg%
What would be the expected test results for calcium and phosphorus in hyperparathyroidism?
increase calcium
decrease phosphorus
What is the purpose of adding stannous chloride, ferrous sulfate, and ascorbic acid in the determination of inorganic phosphorus?
reducing agents
*reduces phosphomolybdate to aminonapthosulfonic acid
Name several things that can affect the level of circulating calcium
Vitamin D
serum protein levels
bone cell activity
What two hormones control serum calcium levels?
PTH and Calcitonin
have an antagonistic relationship
Which electrolyte is the chief plasma base that helps in maintaining osmotic pressure?
sodium
Hemolysis has the greatest effect on which serum levels?
potassium
magnesium
What is the function of aldosterone?
promotes sodium by kidneys, which results in increased water retention, blood vol and BP
What hormone has the most control over serum phosphate levels?
PTH
What is the normal serum osmolality?
275-295 mOsm/kg of H2O