Test 1 Flashcards
The major intracellular cation is
Potassium
The major intracellular cations normal value is
3.5-5.0 mm/L
The major extracellular cation is
Sodium
The major extracellular cation normal value is
136-145 mm/L or mEq/L
The major extracellular anion is
Chloride
The major extracellular anion normal value is
90-109 mm/L
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?
calcium and magnesium
Be able to calculate the anion gap if given values for Na+, K+, Cl-, and CO2. Be able to correlate abnormal anion gaps with other test results (such as BUN) or with instrument/technologist error
-Na+-(Cl-+HCO3-)
8-18 mmol/L
-Na++K-(Cl-+HCO3-)
12-20 mmol/L
To what does % saturation of transferrin refer? What is the normal value?
ratio of serum iron to TIBC
20-50%
What is hypokalemia?
low serum potassium; can be caused by decreased dietary intake, vomiting, renal dysfunction
If tetany is due to calcium, what specific fraction of calcium is involved? Will it be increased or decreased?
decreased ionized Ca2+
What analyte in the blood is used to measure serum phosphorous? What is the normal value for serum phosphorous?
inorganic phosphate
2.7-4.5 mg%
Why is it important to measure serum magnesium levels?
tetany due to magnesium deficiency
In analyzing calcium by atomic absorption, why is lanthanum added?
to prevent interference of phosphate
Calcium exists in serum as ______ and _______. Which one is physiologically active?
- ionized and protein bound
- ionized is physiologically active
A patient with lactic acid acidosis would have an ________ anion gap
increased
What is the purpose of adding magnesium carbonate to an iron binding capacity?
removes excess unbound iron
What does TIBC measure?
estimates transferrin level in serum
What is the Fiske-Subbarow method for phosphorous?
molybdate added to serum to form phosphomolybdate reduces to aminonapthosulfonic acid
There is a _____________ relationship between serum calcium and phosphorous
reciprocal
What is the normal serum calcium level?
8.4-10.2 mg/dL
What would be the expected test results for calcium and phosphorous in hyperparathyroidism?
CA2+ is increased phosphorous is decreased
What is the purpose of adding stannous chloride, ferrous sulfate, and ascorbic acid in the determination of inorganic phosphorous?
reducing agents
Name several things that can affect the level of circulating calcium
serum protein levels, parathyroid hormone, bone-cell activity(osteoclastic activity) Vitamin D
What 2 hormones control serum calcium levels?
calcitonin-increased
parathyroid hormone-decreased (PTH)
Which electrolyte is the chief plasma base that helps in maintaining osmotic pressure?
Na+
Hemolysis has the greatest affect on serum ________levels
potassium/magnesium
What is the function of aldosterone?
increased sodium reabsorption, increased H2O retention, increased BP and blood volume
What hormone has the most control over serum phosphate levels?
parathyroid hormone (PTH)
What is the normal serum osmolality?
275-295 mosm/kg of H2O
What are the four main buffer systems of the body?
bicarbonate/carbonic acid
hemoglobin buffer
plasma proteins
phosphate phosphoric acid/phosphate phosphoric buffer
The pKa of carbonic acid is
6.1
What is added to the reaction mixture in calcium determinations to prevent interference by magnesium?
8-hydroxyl quinoline
What component of a freezing point osmometer actually measures the sample temperature?
thermistor
What 2 properties can be used to measure osmolality?
vapor pressure
freezing point depression
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 PCO2 electrode actually measure?
pH
Respiratory acidosis is an increase of ________while due to respiratory alkalosis decreased exchange of ___________
CO2
During the chloride 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 two portions of the buffer system?
20:1
Normal blood pH is
7.34-7.44 (slightly alkaline)
Most of the CO2 present in the blood is in the form of
bicarbonate
What substance is necessary for the release of oxygen from hemoglobin?
2,3-DPG(diphosphoglycerate)
What happens in the body to compensate for a state of metabolic acidosis?
hyperventilation
What is the cause of metabolic alkalosis?
excess bicarbonate and/or deficit of noncarbonic acid
What is p50?
PO2 at which Hgb is 50% saturated with O2;
equal to 26-27 mmHg
List several precautions that must be used in handling a specimen for ABG’s
anaerobic, 15 mins, place on ice, heparinized, drawn from the artery
Hyperventilation is a common cause of
respiratory alkalosis
What reaction is catalyzed by the enzyme carbonic anhydrase?
carbonic anhydrase breaks down carbonic acid
CO2 + H2O–> H2CO3
formation of carbonic acid from CO2 and H2O
What is the normal range for pCO2? for pO2?
pCO2: 35-45 mmHg
pO2: 80-100 mmHg
In general, respiratory acidosis results from
decreased exchange of CO2 from lungs
increased CO2 hypoventillation
Be able to recognize the Henderson-Hasselbalch equation
pH=pKa + Log
bicarbonate/carbonic acid
A fever of unknown origin would cause a _________ shift of the oxygen dissociation curve while an increased affinity for oxygen causes a _________ shift
right
left
Which anticoagulant is preferred for ABG analysis?
heparin
The pO2 electrode is based on the principle of
amperometric measurement
What would be the breathing pattern of a patient in respiratory alkalosis?
shallow, rapid
What is the compensatory mechanism in respiratory acidosis?
increase bicarbonate concentration in the blood by absorption in the kidneys
What ABG parameter is most useful in assessing a fire victim?
pO2
How would exposure to air bubbles affect an arterial blood sample?
pO2 would increase
pH would increase
pCO2 would decrease
Hyperventilation is the loss of
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
A supercooled solution has a _________temp than its freezing point
lower
Every mole of solute decreases the freezing point of H2O by _______ degrees
1.86 degrees celsius
What is the name of the rapid stirrer mechanism in an osmometer?
vibrator
What are the 4 forms of CO2 in the blood?
bicarbonate (90-95%)
carbonic acid
dissolved CO2(dCO2)
carabamino compounds
When calcium levels decline, which hormone is secreted to restore normal calcium levels
parathyroid
What gases can be measured by a co-oximeter?
carboxyhemoglobin
sulfhemoglobin
methemoglobin
How should the sample for an ABG measurement be mixed?
roll between palms
Name several suitable sites for ABG draws
radial artery, brachial, femoral, temporal
If given value for pH be able to evaluate the acid-base status of the patient
pH:7.35-7.45
If given value for pCO2 be able to evaluate the acid-base status of the patient
pCO2: 35-45
If given value for HCO3-be able to evaluate the acid-base status of the patient
HCO3: 22-26
What is ceruloplasmin?
transport protein for copper
decreased in Wilson’s disease
What is oligoclonal banding and where is it typically seen?
increased CSF IgG and multiple distinct bands in the globulin zone.
seen in 90% of MS patients
