Intro to lab medicine

Question 1

What is screening used for?

Answer 1

to identify risk factors for disease and to detect disease in asymptomatic patients

Question 2

What does screening accomplish?

Answer 2

early intervention, reduce disease morbidity and mortality

Question 3

What are the characteristics of population for optimal screening?

Answer 3

high prevalence of disease, pt likely to be compliant with tests and treatment

Question 4

What are the characteristics of disease for optimal screening?

Answer 4

significant morbidity/mortality, effective treatment available, presymptomatic period detectable, improved outcome from early treatment

Question 5

What are the characteristics for optimal screening tests?

Answer 5

sensitivity, specificity, low cost and risk, confirmatory test available

Question 6

How does screening benefit patient management?

Answer 6

evaluate severity, estimate prognosis, monitor disease, detect disease recurrence, select drugs/therapy

Question 7

How does cost affect screening?

Answer 7

cost of test must be considered, associated risks, potential for additional testing, will results of test change management

Question 8

Define qualitative

Answer 8

either positive or negative; the substance you are testing for is either present or absent

Question 9

What are some examples of qualitative tests?

Answer 9

pregnancy tests, drug screens

Question 10

Define quantitative

Answer 10

measured amt reported in mass or volume

Question 11

Describe reference intervals and what they do

Answer 11

establish the normal range, are dependent on the lab and popn, determined by sampling a healthy popn. 95% of the results determine the normal range

Question 12

What are some physiologic factors which may influence test results?

Answer 12

meds, altitude, occupation, age, gender, excercise, diet, pregnancy, diurnal variations, tobacco

Question 13

Define accuracy

Answer 13

determined by its correspondence with the true value. is maximized by the calibration of lab equipment/quality control measures.

Question 14

Define precision

Answer 14

measure of a test’s reproducibility when repeated on the same sample

Question 15

Define sensitivity

Answer 15

ability of a test to detect the presence of disease. expressed as the % of patients w/disease who test positive

Question 16

What does a test with 90% sensitity mean?

Answer 16

gives positive results in 90% of diseased patients and negative results in 10% of disease patients (false negatives).

Question 17

What is a true positive result?

Answer 17

abnormal test results occurring in individuals who have the disease

Question 18

What is a false negative result?

Answer 18

normal test result occurring in individuals who have the disease

Question 19

Define specificity

Answer 19

ability to detect absence of disease and is expressed as the % of patients without disease in whom the test is negative

Question 20

What does a test with 90% specificity mean?

Answer 20

gives negative results (true negatives) in 90% of patients without disease and positive results (false positives) in 10% of patients without the disease

Question 21

What is a true negative result?

Answer 21

normal test results in a disease-free healthy individual

Question 22

What is a false positive result?

Answer 22

abnormal test results in a disease-free healthy individual

Question 23

What is an example of a highly specific test?

Answer 23

to check for gout would be an evaluation of the jt fluid for the presence of urate crystals

Question 24

What is pretest probability?

Answer 24

the likelihood the patient has the abnormality that you are testing for based on risk factors, symptoms, h/o, physical exam

Question 25

How do you decide btw single test ordering or panels?

Answer 25

single tests may be less expensive then the whole panel. depends on what you are looking for and the patient popn

Question 26

What are some common profiles (panels)

Answer 26

lipid, thyroid, prenatal screening, arthritis, hepatitis, antinuclear antibodies, coagulation

Question 27

What does the CPT code stand for?

Answer 27

current procedural terminology, every diagnostic procedure has a CPT code

Question 28

What does the ICD-9 code stand for?

Answer 28

international classification of disease, every diagnosis has an ICD-9 code

Question 29

What does DRG stand for?

Answer 29

diagnoses related group, patient ICD-9 is assigned to a DRG

Question 30

How are CPT codes related to ICD and DRGs?

Answer 30

approved CPT codes are linked to ICD codes and DRGs

Question 31

What is included in an electrolyte panel?

Answer 31

Na, K, Cl, CO2

Question 32

What is included in a basic metabolic profile?

Answer 32

Na, K, Cl, CO2, GLU, BUN, Creat, Ca

Question 33

What is included in a comprehensive metabolic panel?

Answer 33

Na, K, Cl, CO2, GLU, BUN, Creat, Ca, TP, ALB, AST, (ALT), ALP, T.BILI, D.BILI

Question 34

What is included in a LFT?

Answer 34

ALB, AST, ALP, T.BILI, D.BILI

Question 35

What is included in a renal fxn panel?

Answer 35

Na, K, Cl, CO2, GLU, BUN, Creat, Ca, (ALB), Inor P