03/09g Lab Tools of Evidence-Based Medicine I Flashcards

1
Q

What is anatomic pathology?

A

Disease diagnosis based on gross and microscopic examination of patterns in tissues, organs, and whole bodies

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2
Q

What is clinical pathology?

A

Disease diagnosis based on laboratory analysis of bodily fluids or tissues

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3
Q

What does a clinical pathologist do?

A

Serves as a liaison of knowledge between the technical aspects of the lab and actual clinical practice
Makes sure that labs are in compliance with the FDA, OSHA, etc.
Consults with clinicians to guide lab test ordering, interpretation of lab values, and clinical decision-making based on lab data

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4
Q

Why order a lab test??

A

1) Confirm a clinical impression
2) Rule out a diagnosis
3) Monitor therapy/disease course
4) Establish prognosis
5) Screen for disease
6) Prevent liability

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5
Q

What does the chemistry lab do? List some specific tests

A

Analyzes chemical components of blood, serum, urine, body fluids, etc.
Tests - electrolytes, tissue enzymes, blood gas, urinalysis

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6
Q

What does the microbiology and immunology lab do? List some specific tests

A

Cultures and identifies infectious organisms and the body’s immune response to them
Tests - cultures, antibiotic sensitivity, Gram stain

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7
Q

What does the serology lab do? List some specific tests

A

Analyzes the response (antibody levels) to infection, tumor, non-neoplastic disease, and immunization
Tests - tumor markers, infectious organisms antibody titers

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8
Q

What does the molecular diagnostics lab do? List some specific tests

A

Analysis of genetic material, including single genes and chromosomes from both humans and pathogens
Tests - chromosomal abnormalities, prognostic indicators, infectious organisms identification

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9
Q

What does the toxicology lab do? List some specific tests

A

Analyzes toxins, drug levels, and environmental and therapeutic insults
Tests - heavy metal poisoning, antibiotics, levels of chemotherapeutic agents

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10
Q

What do the blood bank and transfusion services do?

A

Provide blood products for patients who need them (everyone!)
Consult on patients with transfusion issues (compatibility testing)
May be responsible for blood collection and blood product manufacturing (if you don’t do this, you’re NOT a blood bank!)

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11
Q

What does the hematology and coagulation lab do?

A

Analyzes blood and bone marrow, focusing on cellular elements and coagulation factors, and consults on hematologic disorders
Tests - CBC, platelet counts, hemoglobin, PT and PTT, factor levels

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12
Q

What is the difference between precision and accuracy?

A

PRECISION is the ability of a test to produce nearly identical values when repeated under identical conditions (repeatability)
ACCURACY is the ability of a test to produce results that are close to the “true” measurement

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13
Q

What is a reference range?

A

A range of acceptable values for an analyte, based on a healthy cohort
Lots of things can impact what is “healthy”

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14
Q

Do reference ranges capture all normal values?

A

NO!
No, no, no, no
NO.

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15
Q

What is a “gold standard” test?”

A

The Best Way to test for a specific disease, against which all other lab tests are compared

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16
Q

What is the sensitivity of a test?

A

The probability of getting a positive result in a diseased patient
Lots of false negatives = poor sensitivity

17
Q

What is the specificity of a test?

A

The probability of getting a negative result in a disease-free patient
Lots of false positives = poor specificity

18
Q

What is the positive predictive value?

A

The probability of having a disease, given a positive test result (what patients actually care about!)

19
Q

What is the negative predictive value?

A

The probability of being disease-free, given a negative test result (again, what patients actually care about!)

20
Q

What two factors determine the predictive value of a lab test?

A

1) The accuracy of the test

2) The prevalence of the disease in the population - this very strongly impacts the predictive value of the test!

21
Q

What is a ‘critical result?’

A

A lab value that varies so greatly from normal that is represents a life-threatening pathophysiologic state