Labs & Markers Flashcards

47, 48, 49

1
Q

Which lab tests should be performed on a patient to rule out secondary causes of dyslipidemia?

A

fasting blood glucose (DM), TSH (hypothyroidism), serum creatinine (renal function), UA for proteinuria (kidneys), alkaline phosphatase (liver)

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2
Q

Patients with clinical and angiographic evidence of coronary artery disease tend to have higher plasma levels of …?

A

homocysteine

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3
Q

It is indicated to check homocysteine levels in which kind of patients?

A

high-risk patients with family hx of premature atherosclerosis or arterial occlusive disease

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4
Q

High levels of high-sensitivy C reactive protein have been show to show what?

A

strong independent predictor of cardiovascular and peripheral vascular disease risk and of recurrent cardiac events in patients with history of CAD or Acute coronary syndrome (ACS)

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5
Q

What are the hsCRP values that we should know?

A

> 3mg/L → marker of high risk for death and MI
1-3 mg/L → intermediate risk
<1.0 mg/L → low risk

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6
Q

What components are included in a basic metabolic panel (BMP)?

A

Sodium, Potassium, Calcium, Chloride, Carbon Dioxide, Glucose, BUN, Creatinine

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7
Q

A complete metabolic panel has all components of a BMP and what else?

A

Alkaline Phosphatase, Total Bilirubin, AST/ALT, Total Protein, Albumin

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8
Q

If looking to evaluate liver and kidney function, which metabolic panel would be best?

A

CMP

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9
Q

If albumin levels are low, what other lab level will also be low?

A

calcium, half of calcium is bound to Albumin - need to calculate corrected calcium level

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10
Q

What are indications for ordering a metabolic panel?

A

aid in determining diagnosis, follow course of condition or treatment plan, monitor electrolytes, screen for occult disease

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11
Q

In what heart condition would you see decreased Na levels in a metabolic panel?

A

CHF

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12
Q

What electrolyte level is critical to monitor if a patient is on diuretic and/or other heart meds?

A

Potassium

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13
Q

What can high K levels cause?

A

arrhythmias!

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14
Q

Which particular lab value serves as an index of both kidney and liver function?

A

BUN

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15
Q

What is better than BUN in indicating renal disease?

A

creatinine

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16
Q

How do albumin and AST/ALT evaluate the liver?

A

Albumin tests liver function, where as AST/ALT tell you the integrity of the hepatocytes themselves (inflammation, breakdown). Both will tell you if you have liver disease, and how bad it is.

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17
Q

True/False it is uncommon to have a isolated abnormality on a metabolic panel?

A

True. You are usually confronted with a group of abnormal values. Exception: glucose

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18
Q

What is considered the old gold standard for myocardial injury?

A

creatine kinase (CK) has excellent sensitivity but poor specificity

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19
Q

CK levels will rise sharply after the onset of chest pain associated with an acute MI. But, other causes for increased CK include:

A

any musculoskeletal injury, IM injection, certain medications

20
Q

What is the isoenzyme of CK that is most specific for myocardial tissues?

A

CK-MB

21
Q

What is the biochemical marker of choice in the evaluation of patients with ACS?

A

cardiac-specific Troponins! (more specific than CK-MB)

22
Q

Troponins are most beneficial in identifying AMI how many hours or more after symptoms onset?

A

Typically 6 (3-12 hr range), and will persist for 7-10 days

23
Q

If a patient’s troponins are normal at presentation, but the clinical index of suspicion is very high, when should the troponin levels be assessed in again?

A

In 6-12 hours

24
Q

Which cardiac marker is preferred for early detection of an AMI?

A

Myoglobin

25
Q

How soon are elevated myoglobin levels detected and when do they return to normal?

A

Show 1-4 hours after onset of symptoms and peak 6-7 hours after. Will return to normal 24 hours post-MI

26
Q

If you suspect a patient has Venous thromboembolism (VTE) which lab test should you order?

A

d-Dimer (used to diagnose thrombotic disorders)

27
Q

Is d-Dimer specific for VTE?

A

No. A negative result can help rule out VTE/PE/DVT/DIC. But it is not specific enough to diagnosis VTE.

28
Q

What other things can cause a positive d-Dimer test besides VTE?

A

malignancy, DIC, infection, inflammation, pregnancy

29
Q

True/False. If myoglobin in normal in the first 6 hours, an MI is very unlikely.

A

True

30
Q

What lab value aids in differentiating a patient’s dyspnea from heart failure and non cardiac causes?

A

B-natriuretic peptide (BNP)

31
Q

BNP is more specific in which patients, and less so in which?

A

Circulating levels of BNP increase in proportion to the severity of HF, and BNP is detectable even with minimal clinical symptoms.

32
Q

A patient has a heart attack and 3 days later is having chest pain with an elevated Myoglobin level. What is the most likely cause?

A

Re-infarction. Myoglobin goes back to normal within 24 hours of MI, so a new rise indicates a new attack.

33
Q

What other things can cause an elevated troponin?

A

CHF, pulmonary embolism, renal failure, rhabdomyolysis, kidney injury, any other things that can have repercussions on the heart.

34
Q

Typical criteria for diagnosis of AMI requires total CK elevation of how much?

A

twofold above normal

35
Q

Which lab test has a rough correlation with the size of the infarction?

A

CK-MB

36
Q

A relative index can be used to differentiate a cardiac cause vs a muscle cause of an elevated CK-MB. What is it?

A

CK-MB/total CK x 100. If is greater than 2 indicated myocardial necrosis

37
Q

61 year old woman with a history of tobacco abuse and fam hx of CAD presents to ED after 1 hr of chest “discomfort”. EKG shows normal sinus rhymth. Which lab test do you order?

A

Myogblobin - is the earliest marker for AMI

38
Q

Which lab value is both high specific and sensitive to ruling in or out MI?

A

Troponin I - if normal, essentially can R/O MI, if elevated, confirms MI

39
Q

Patient has elevated D-dimer and Troponin T, what is most likely cause?

A

PE

40
Q

How routinely do you draw for cardiac markers?

A

Depends on your institution - but frequently at 0, 4, 8, 12, hours OR 6-8 hours for 24 hours

41
Q

If initial testing indicates a hs-CRP level that is very high (>10), the test should be repeated when?

A

in about 2-3 weeks

42
Q

Is Lipoprotein-A (an LDL-like particle) included in a routine lipid panel?

A

No. But it is thought to contribute to atherosclerosis, but NCEP does not recommend widespread screening.

43
Q

In who would a Lp-A level check be indicated in?

A

Pts with lipid disorders, intermediate cardiovascular risk, or a strong family history of premature CVD

44
Q

Conditions that are associated with an elevated BNP:

A

HF, LVH, myocarditis, pulmonary hypertension

45
Q

For patients with CHF, BNP levels will generally be above____?

A

100 pg per mL (usually normal values are <50)