Cobas

Question 1

PCO2 electrode

Answer 1

Severinghouse electrode
pH electrode immersed in bicarbonate buffer solution
Measures ions directly as pH changes due to diffuse of PCO2 across membrane changing the pH of the buffer solution

Question 2

PO2 electrode

Answer 2

Clark electrode
Constant polarizing voltage is applied to Ag/Ag Cl anode and platinum wire cathode immersed in KCl solution
O2 crosses membrane and current is produced which is proportional to rate of O2 reduction

Question 3

Total Hgb measurement

Answer 3

Measurement of Hgb derivatives: oxyHgb, deoxyHgb, carboxyHgb, methemoglobin, sulfHgb
Determined spectrophotometrically, absorbable measured using charge coupled device CCD which uses full spectrum of wavelengths 520-650 nm

Question 4

Acceptable types of specimens

Answer 4

Whole blood 
Plasma 
Serum 
Serous body fluids 
Not urine

Question 5

Acceptable anticoagulants

Answer 5

Lithium heparin
Sodium heparin
Balanced heparin salts

Question 6

Specimen storage and stability

Answer 6

Analyzed immediately
PCO2 and PO2 must be analyzed within 30 minutes of collection or redrawn
Collected on ice
Capillary tube specimens should be analyzed within 30 minutes and kept horizontal until run

Question 7

Criteria for unacceptable specimens

Answer 7

Clotted specimen

Question 8

PH normal range

Answer 8

7.35-7.45 pH units

Question 9

PO2 normal range

Answer 9

80-100 mmHg

Question 10

PCO2 normal range

Answer 10

35-45 mmHg

Question 11

TCO2 normal range

Answer 11

23-27 mmol/L

Question 12

HCO3 normal range

Answer 12

22-26 mmol/L

Question 13

Base excess normal range

Answer 13

-/+ 2 mEq/L

Question 14

O2Hb (oxyhemoglobin) normal range

Answer 14

95-98%

Question 15

HHb (deoxyhemoglobin) normal range

Answer 15

1.4-4.9%

Question 16

COHb (carboxyhemoglobin) normal range

Answer 16

Non smoker 0.5-1.5%

Smoker 8-9%

Question 17

Congestive heart failure characteristics

Answer 17

Decreased PO2

Increased pCO2

Question 18

Barbiturate intoxication characteristics

Answer 18

Decreased pO2

Increased pCO2

Question 19

Pulmonary emphysema

Answer 19

Decreased pO2

Increased pCO2

Question 20

Asthmatic bronchitis characteristics

Answer 20

Decreased pO2

Increased pCO2

Question 21

Prolonged vomiting characteristics

Answer 21

Increased pCO2

Question 22

Excessive intake of bicarbonate for GI distress characteristics

Answer 22

Increased pCO2

Question 23

Respiratory acidosis characteristics

Answer 23

PH low
CO2 high
Caused by hypoventilation, COPD, emphysema, or strangulation
Kidneys compensate by increased tea sorority of HCO3

Question 24

Respiratory alkalosis characteristics

Answer 24

PH high HCO3 low
Caused by hyperventilation
Kidneys compensate by decreasing reabsorption of HCO3

Question 25

Metabolic acidosis characteristics

Answer 25

Ph low
HCO3 low
Caused by accumulation of fixed acids, diarrhea and Addison’s disease
Lungs compensate by blowing off CO2

Question 26

Metabolic alkalosis characteristics

Answer 26

Ph high
HCO3 high
Caused by loss of fixed acids, vomiting and taking bicarbonate
Respiratory rate is decreased to compensate

Question 27

Ph electrodes

Answer 27

Glass capillary electrode

Reference electrode