Common Laboratory Tests

Question 1

pH

Answer 1

7.35-7.45
<7.35 acidosis
>7.45 alkalosis

Question 2

PaCO2

Answer 2

Provides info on how well the lungs are able to remove CO2.
35-45 mmHg
<30 alveolar hyperventilation
>50 alveolar hypoventilation, ventilatory failure

Question 3

PaO2

Answer 3

Provides info on how well lungs are able to oxygenate the blood.
80-100 mmHg

Question 4

HCO3-

Answer 4

Bicarbonate is a component of the chemical buffering system that keeps blood from becoming too acidic or basic.
22-26 mEq/L

Question 5

SaO2

Answer 5

Percent O2 saturation of hemoglobin.

95-98%

Question 6

Eucapnia

Answer 6

Normal level of CO2 in arterial blood

Question 7

Hypercapnia

Answer 7

Elevated level of CO2 in arterial blood

Question 8

Hypocapnia

Answer 8

Low level of CO2 in arterial blood

Question 9

Hypoxemia

Answer 9

Low level of O2 in arterial blood

Question 10

Mild hypoxemia

Answer 10

PaO2 60-79 mmHg, SaO2 90-95%

Question 11

Severe hypoxemia

Answer 11

PaO2 <40 mmHg, SaO2 < 60%

Question 12

Hypoxia

Answer 12

Low level of O2 in tissue despite adequate perfusion

Question 13

Cardiac Biomarkers

Answer 13

Enzymes leak out of heart into blood after MI.
Creatine phosphokinase-MB appears in blood about 4 hours after MI, peaks at 12-24 hours and declines over 48-72 hours.
Troponin-I remains elevated for 5-7 days.

Question 14

Cholesterol Test

Answer 14

Measures amount of cholesterol and triglycerides in the blood in order to determine the risk of atherosclerosis. Includes a measure of 4 types of lipids:

1) Total cholesterol
2) High density lipoprotein (HDL) - good cholesterol that helps carry away LDL and protects against atherosclerosis
3) Low density lipoprotein (LDL) - associated with buildup of fatty plaques
4) Triglycerides - body converts any calories it does not need to use right away into triglycerides, which are stored in adipose tissue.

Question 15

Complete blood count (CBC)

Answer 15

Measures RBC count, total WBC count, WBC differential, platelets, hemoglobin, and hematocrit.

Question 16

Hematocrit (HCT)

Answer 16

Percentage of RBC in total blood volume.
Low hematocrit may indicate anemia, blood loss, and vitamin or mineral deficiencies.
High hematocrit may indicate dehydration or polycythemia vera (condition that causes overproduction of RBC)

Question 17

Partial Thromboplastin Time (PTT) and Prothrombin Time (PT)

Answer 17

Measure how quickly the blood clots. Used to measure oral anticoagulant therapy or to screen for blood disorders.
PTT is more sensitive than PT in detecting minor deficiencies.

Question 18

Respiratory acidosis

Answer 18

PaCO2 > 45 mmHg

pH <7.4

Question 19

Retention of CO2 to compensate for metabolic alkalosis

Answer 19

PaCO2 > 45 mmHg

pH > 7.4

Question 20

Respiratory alkalosis

Answer 20

PaCO2 < 35 mmHg

pH >7.4

Question 21

Elimination of CO2 to compensate for metabolic acidosis

Answer 21

PaCO2 <35 mmHg

pH <7.4

Question 22

Metabolic acidosis

Answer 22

HCO3- <22 mEq/L

pH <7.4

Question 23

Renal compensation for respiratory alkalosis

Answer 23

HCO3- <22 mEq/L

pH >7.4

Question 24

Metabolic alkalosis

Answer 24

HCO3- >26 mEq/L

pH >7.4

Question 25

Renal compensation for respiratory acidosis

Answer 25

HCO3- >26 mEq/L

pH <7.4

Question 26

Moderate hypoxemia

Answer 26

PaO2 40-59, SaO2 60-90%