Electrolyte and Acid/Base

Question 1

Blood pCO2 may be determined by:

Answer 1

using a nomogram from the blood pH and total CO2 concentration

Question 2

In the potentiometric measurement of hydrogen ion concentration, the reference electrodes is composed of:

Answer 2

silver-silver chloride

Question 3

Which of the following electrodes is based on the principle of amperometric or amperometric-polarographic measurement?

Answer 3

pO2 electrode

Question 4

Most of the carbon dioxide present in the blood is in the form of:

Answer 4

bicarbonate ion

Question 5

Serum “anion gap” is increased in patients with:

Answer 5

lactic acidosis

Question 6

At a blood pH of 7.40 what is the ratio of bicarbonate to carbonic acid?

Answer 6

20:1

Question 7

The buffering capacity of blood inside RBCs is maintained in acidosis by a reversible exchange process between bicarbonate and:

Answer 7

chloride

Question 8

Acidosis and alkalosis are best defined as fluctuations in blood pH and CO2 content due to changes in the :

Answer 8

Bicarbonate buffer system

Question 9

A common cause of respiratory alkalosis is:

Answer 9

hyperventilation

Question 10

Partially Compensated Metabolic acidosis is described as a(n)

Answer 10

decrease in TCO2 content and pCO2 with a decreased pH

Question 11

Partially Compensated Respiratory acidosis is described as a(n):

Answer 11

increase in TCO2 content and pCO2 with a decreased pH

Question 12

Unless blood gas measurements are made immediately after sampling, in vitro glycolysis of the blood causes a:

Answer 12

fall in pH and a rise in pCO2

Question 13

Hydrogen ion concentration (pH) in blood is usually determined by a pair of electrodes. Indicate the pair of electrodes

Answer 13

Ag/AgCl2 reference electrode
glass measuring electrode

Question 14

Specimens for blood gas determination should be drawn into a syringe containing:

Answer 14

heparin

Question 15

What is the Henderson-Hasselbalch equation?

Answer 15

pH = pKa + log (salt/acid)

Question 16

A potassium level of 6.8 mEq/L is obtained. Before reporting the results, the first step the medical laboratory scientist should take is to:

Answer 16

check the serum for hemolysis

Question 17

Arterial blood collected in a heparinized syringe but exposed to room air would cause which of the following changes in the specimen?

Answer 17

pO2 = Elevated
pCO2 = Decreased
pH = Elevated

Question 18

A potentiometric electrode that measures an analyte that passes through a selectively permeable membrane and rapidly enters into equilibrium with an electrolyte solution is:

Answer 18

pCO2

Question 19

Coulometry/amperometry is used to measure:

Answer 19

chloride

Question 20

Ion selective electrodes are called selective rather than specific because they actually measure the:

Answer 20

activity of one ion much more than other ions present

Question 21

the electrolyte chloride

Answer 21

It is the main anion of the extracellular fluid
It can shift from the extracellular plasma to the intracellular fluid of red cells depending upon body pH
It can be measured in serum, urine and sweat.

Question 22

Most automated blood gas analyzers directly measure:

Answer 22

pH, pCO2, and pO2

Question 23

Which blood gas electrode is composed of calomel and glass?

Answer 23

pH

Question 24

Valinomycin enhances the selectivity of the electrode used to quantitate:

Answer 24

potassium

Question 25

Potassium is an electrolyte that may be best described as:

Answer 25

the major cation of intracellular fluid

Question 26

An electrode has a silver/silver chloride anode and a platinum wire cathode. It is suspended in a KCl solution and separated from the blood to be analyzed by a selectively permeable membrane. Such an electrode is used to measure?

Answer 26

pO2

Question 27

In respiratory acidosis, the most common compensatory mechanism is the increased in:

Answer 27

plasma bicarbonate concentration

Question 28

The presence of only slightly visible hemolysis can significantly increase the serum level of:

Answer 28

potassium

Question 29

Correction of pH for a patient with a body temperature of 38C would require:

Answer 29

Subtraction of 0.015

Question 30

Which is associated with both metabolic and respiratory alkalosis?

Answer 30

Hypokalemia

Question 31

Primary aldosteronism results from a tumor of the adrenal cortex. In the extracellular fluid (blood stream) this would cause:

Answer 31

Increased sodium, decreased potassium

Question 32

A patient diagnosed with Addison’s disease has a serum sodium and potassium analyses performed. What would the results reveal?

Answer 32

Low sodium, high potassium levels

Question 33

Which electrolyte measurement is least affected by hemolysis?

Answer 33

Calcium