LAB VALUES

Question 1

Creatinine Kinase (CK)

Answer 1

Normal Values 51-294 u/L

RISE 4-6 hours following MI
PEAK at 24 hours (earlier with thrombolytic therapy)
BASELINE 48-72 hours after MI

in all striated muscle catalyzing the phosphorylation of creatine to creatine phosphate-not specific

Question 2

Creatinine Kinase-MB (CK-MB)

Answer 2

Normal Values <5.5 ng/ml [An isoenzyme of CK found predominantly in cardiac muscle]

RISE 3-4 hours following MI
PEAK 8 hours
BASELINE 24-36 hours after MI

Sensitive (small MI’s may be missed)
Relatively specific to cardiac muscle

Question 3

Cardiac-specific Troponin T (cTnT)

Cardiac-specific Troponin I (cTnI)

Answer 3

Critical Values ≥ 0.45 ng/ml [Specific proteins responsible for regulating the calcium mediated contractile process of cardiac muscle]

RISE 3-4 hours following MI
PEAK at 16 hours
BASELINE
cTnT 10-14 days after MI
cTnI 7-10 days after MI

Highly sensitive;
Very specific

Question 4

Myoglobin

Answer 4

RISE 1-3 hours following MI
PEAK at 6 hours
BASELINE 12-18 hours

High sensitivity (negative predictive value)
Not specific (Protein common to all striated muscle, not cardiac specific)

Question 5

B-Type Natriuretic Peptide (BNP)

Answer 5

Detect heart failure

BNP < 100 pg/mL -> Heart failure very unlikely
BNP 100-400 pg/mL -> Intermediate likelihood
BNP > 400 pg/mL -> Heart failure very likely

Question 6

Hgb

Answer 6

Men 13 - 18 g/dL
Women 12 - 16 g/dL

*of <8 g/dL do not exercise risk of coronary ischemia

Question 7

Hct

Answer 7

Men 38 - 52%
Women 35 - 47%

*A Hct of < 30% do not exercise risk of coronary ischemia

Question 8

WBC

Answer 8

3.5 - 9.1 x 103 cells/µL

High : do not exercise if also have fever of ≥ 101º F. (increased risk of coronary ischemia)

Decreased =Viral infx, cancers, extreme age, AIDS
Increased =Bacterial infx, leukemia, allergic reactions, parasitic infections

Question 9

Platelets

Answer 9

165 - 415 x 103 cells/µL

Low –> risk spontaneous bleeding and activity may be restricted

<30k NO Chest PT
< 5 - 10 x 103 cells/µL strict bedrest

Question 10

Platelets >150,000 /µL

Answer 10

Unrestricted resistance

Question 11

platelets 80,000-150,000 /µL

Answer 11

Moderate resistance

Question 12

Platelets 50,000-80,000 /µL

Answer 12

Minimal resistance

Question 13

Platelets <50,000 /µL

Answer 13

NO resistance

Question 14

Platelets 10,000-20,000 /µL

Answer 14

Possible transfusion

Question 15

Platelets <10,000 /µL

Answer 15

Bed rest, ADLs only, Transfusion is necessary

Question 16

Prothrombin Time (PT)

normal seconds?
therapeutic values?

Answer 16

Normal Values: 11 - 13 seconds (clotting time)

Therapeutic Values: 1.5 - 2.5 x the reference range

• Low values do not contraindicate therapy
• High values put the patient at increased risk of spontaneous bleeding. The physician should be consulted regarding therapy

Question 17

International Normalized Ratio (INR)

Answer 17

ratio of the Prothrombin Time to the reference range

Therapeutic values depend on treatment rationale with adjustments for individual medical history

DVT prophylaxis ~2-3.0
Mechanical heart valve ~2.5-3.5

Considerations for Exercise
***High values put the patient at increased risk of spontaneous bleeding. The physician should be consulted regarding therapy.

Question 18

Activated Partial Thromboplastin Time (APTT, PTT)

what it is

normal values

therapeutic values

consideration for exercise

Answer 18

screen for bleeding disorders and measure effectiveness of heparin therapy

Normal Values: 24-35 seconds (clotting time)

Therapeutic Values: 1.5-2.5 x the reference range (normal value)

Considerations for exercise
APTT >100 seconds signifies spontaneous bleeding
Confer with MD prior to exercise

Question 19

PTT >100 seconds

Answer 19

signifies spontaneous bleeding

Confer with MD prior to exercise

Question 20

Na+

Answer 20

136-146 mmol/L

LOW–>intracellular fluid shift, specifically, brain cell swelling

HIGH–>extracellular fluid shift increasing the risk for intracranial hemorrhage

Both situations cause a decrease in mental status Therapy decisions are based on the patient’s ability to participate

Question 21

Potassium (K+)

Answer 21

Normal Values 3.6-5.0 mmol/L

DO NOT EXERCISE:
K+ <3.2
or K+>5.1

Abnormal K+–>life threatening b/c risk cardiac dysrhythmias

Question 22

Chloride (Cl-)

Answer 22

Normal Values 102-109 mmol/L

Decreased Values: Excessive Sweating, vomiting, diarrhea, heart failure

Increased Values: Dehydration, renal failure, diabetes

Considerations for Exercise=No significant effect

Question 23

Carbon Dioxide (CO2)

Answer 23

Normal Values 22 - 30 mmol/L

Low values if uncompensated may cause a decrease in mental status limiting the patient’s ability to participate in therapy

Question 24

Blood Urea Nitrogen (BUN)

Answer 24

Normal Values 7-20 mg/dL

High levels do not contraindicate exercise
Patients with renal failure may also be anemic which often decreases their exercise tolerance

Question 25

Creatinine (Cr)

Answer 25

Normal Values 0.6-1.2 mg/dL

Cr is a waste product of muscle metabolism

Increased Values–Renal Dysfunction

Considerations for Exercise
High levels do not contraindicate exercise
Patients with renal failure may also be anemic which often decreases their exercise tolerance

Question 26

Blood Glucose (BG)

Answer 26

Normal Values 75 - 100 mg/dL

Low serum levels result in poor exercise tolerance, decreased mental status, and if prolonged, are life-threatening

• **A BG <70 mg/dL is a contraindication to exercise
• *A BG >300 mg/dL is a contraindication to exercise (type I + also Type II diabetics with sx or with known ketones in urine)

for the diabetic consider a snack BG <80 mg/dL (ACSM) or <100 mg/dl (AACVPR) before vigorous exercise

Question 27

Glycosylated hemoglobin (HgbA1c)

Answer 27

Demonstrates glucose control over previous 6-12 weeks
< 5.7% Decreased risk of DM
5.7-6.4% Increased risk of DM
≥ 6.5% Consistent with Dx of DM

The goal for a diabetic is < 7%

Question 28

Magnesium (Mg+)

Answer 28

Normal values 1.5-2.3 mg/dL

***Hypo or hypermagnesemia can be life threatening ==> risks of ventricular dysrhythmias.

Low blood levels, more common than high levels. Chronically low levels of Mg+ can cause hypokalemia and hypocalcemia.