Cardiac Panels

One time lab refused to report a trop for one of my patients because it was "too high" and we had to wait until he flipped into an unstable rhythm to get him to the cath lab. So I have beef with lab.

skeletal muscle, myocardium, brain

Major sources of CK

Muscle tissue damage (sensitive not specific)

Clinical significance of CK (Note: correlates to patients muscle mass)

3-4 (rises quick-like)

How long does CK stay in the circulation?

CKMB

What CK is specific to heart injuries?

muscular dystrophy, Rhabdo, hypothyroidism, reye’s

High CKMM can be a biomarker for

trauma, kidney injury, toxins/drugs

Besides heart injuries what else causes a rise in circulating CKMB?

normal childbirth, malignant tumors, shock syndrome

CKBB rises in the case of

reflex

If CK is elevated the lab should run __________ test that break the CK down into isoezymes.

CKMM

What CK is a major component of serum and makes up most of the circulatory total in a healthy person?

CK

What is the 1st cardiac enzyme to rise?

CKMB

Which CK peaks first after an acute MI?

CKMM (3-4 days)

Which CK last longer after an acute MI?

cardiac

If you have a high CK-MB relative index (RI) (above 5%) what are we thinking team?

(CKMB/total CK) X 100

How is CKMB RI calculated

Exercise, trauma, age, gender, early pregnancy, supplements

What factors affect CK interpretation?

Rhabdomyolysis (rhabdo)

A condition that is the result of damaged muscle tissue most often due to traumatic injuries (crush), drugs, toxins, infections, ischemia that can be fatal if left untreated.

CK 5X normal

What is a red flag for rhabdo?

unable to complete task/finish workouts, severe muscle cramps/pain, very dark urine

Signs of rhabdo

Supportive care

Patient presents to the ER for muscle pain and weakness. Patient reports a history of meth use, last used 2 hours ago. Nursing staff reports that the urine sample collected was dark in color. CK level is like 5000. What’s our treatment plan?

Troponin I/T

What is the 1st biomarker to look at in an MI

some type of damage to cardiac muscles

An elevated troponin I is a sign of

Same sensitivity as CKMB, Highly specific for MI (20x normal 3-12 hours post chest pain)

Describe the sensitivity and specificity of troponin I

5-10 days (good for late diagnosis)

How long does troponin I last in the system

12-24 hours

When does troponin I peak?

troponin I

A 56 y/o female presents to the ER 6 days after a episode of chest pain. She states she didn’t want to make a big fuss about it but her daughter implored her for chest pain. What cardiac biomarker could still be elevated, if she had an MI?

consistent with myocardial damage

Any troponin over 1.5 is

high sensitivity trop I

What is internationally accepted as a standard biomarker for MI?

microclots, hemolysis, skeletal muscle disease

What can cause a false increase in cardiac troponin?

autoantibodies, hemolysis, supplements

What can cause a false decrease in cardiac troponin?

myoglobin

What heme protein can be picked up in the urine 2-4 hours after an acute MI?

skeletal/cardiac muscles

Where is myoglobin found?

high, low

Describe the sensitivity and specificity of myoglobin

MI, angina, muscle trauma, renal trauma, open heart surgery, myopathies, IM injections, electric shock, vigorous shock

A high myoglobin could be a sign of what

BNP (B-type natriuretic peptide)

A patient presents to the ER with peripheral edema. What lab test needs to be included in the work up?

AST (aspartate aminotransferase)

What lab test (usually used for the liver) may also be elevated after an MI since it is found in the heart, liver, and skeletal muscles?

lactate dehydrogenase (LD, LDH)

What enzyme catalyzes the interconversion of lactate and pyruvate that can be found in the kidney, liver, and heart?

MI, hemolysis (pre analytical error), liver cirrhosis/necrosis, muscular dystrophy, pernicious anemia, malignancy

What might cause an elevation in LD

LD 1 (heart) and LD 2 (serum)

If LD is high (above 180) the lab will perform isozyme refractive testing, that breaks up _____________________.

Acute MI

If LD 1 > LD2 or if the LD1/LD2 ratio is 0.8 what are we thinking ?

lung disease, congestion, leukemia, lymphoma, and other malignancies, collagen disease, viral infections

Elevation of LD3 and LD4 is consistent with

liver disease, type 1 muscle fiber injury

Elevation of LD5 is consistent with